The battle for F1's most coveted seat

When Nico Rosberg unexpectedly retired from Formula 1 as its new world champion at the end of 2016, Mercedes boss Toto Wolff said almost every other driver on the grid called to enquire about the sudden vacancy at F1's undisputed top team. Wolff reckoned the only reason Kimi Raikkonen and Daniil Kvyat didn't come calling was because they didn't have his number in their contacts list.

It's indicative of the sheer force Mercedes has become during F1's V6 era that most drivers would leap at the chance to race one of its cars should a seat become available. As much as F1 might pray things change in 2018, nothing about the way '17 ultimately played out suggests the Silver Arrows is suddenly about to be toppled from its lofty pedestal.

Sure, Ferrari had a valiant stab and Red Bull won a few races at the tail end of last season - both welcome developments after three years of Mercedes domination - but even saddled with an initially overweight and tyre-hungry car, Mercedes still ultimately topped both championship tables quite comfortably.

Even at its most vulnerable, Mercedes couldn't be beaten. The way this team works so diligently to destroy its own weaknesses, it is unlikely to present rivals with another open goal to aim at. McLaren boss Zak Brown reckons Mercedes could be title favourite for the next three years at least.

Cue another bout of covetous glances in the direction of Mercedes incumbents Lewis Hamilton and Valtteri Bottas. Few in F1 wouldn't wish to trade places with them if possible. Maybe, it will be. The problem when Rosberg retired was that he broke a recently-agreed two-year contract when most of his rivals were contractually unavailable. So late was Rosberg's move that Mercedes had to jump through hoops to prise Bottas out of Williams and into Nico's seat.

As we head into 2018 things are much more volatile. Bottas signed a single-year contract extension last summer, so only has one more season of guaranteed employment to look forward to, while Hamilton has yet to finalise an extension to his five-season stint at Mercedes beyond the end of this year.

Meanwhile, a host of other top drivers - Sebastian Vettel and Max Verstappen being the notable exceptions - head into this campaign contractually available at the end of it, surely with keen eyes on developments at Brackley, which is currently the most serious game in town if you have short-term ambitions to be F1 world champion.

Hamilton is widely tipped to sign a new contract at some point soon. The four-time world champion seems keen and Wolff reckons it is "only a matter of time" before the deal is sealed.

On the other side of the garage, things are less clear cut. Bottas enjoyed a decent first season at the very front of the grid, but he hasn't yet done enough to convince Mercedes he's the right driver for it in the longer term.

Last season was about proving he could at least cut it at the front of the field. Three wins, 13 podiums and four pole positions suggest he is on the right track. Being a good team player and not upsetting the star of the show helps too - especially after the prior stress of the Hamilton/Rosberg era.

But what next? How does Bottas take the next step and show he is a driver capable of carrying Rosberg's mantle, but taking the fight to Hamilton and the rest without upsetting the delicate equilibrium of Mercedes' collective effort? Too aggressive and it could all cave in around him; too reticent and he will surely be kicked to the kerb in favour of one of those who covet his seat.

Bottas agrees he occupies the most sought-after berth in F1 and, having opted to take more control of his own managerial affairs off-track, realises he must pay close attention to the market. The key for him is not to become overly burdened by off-track concerns, while calculating how to take that vital leap from race winner to title contender on it.

"The first thing I need to remember is not to think about it too much!" he tells Autosport, as we discuss the year ahead in a Helsinki hotel. "For me, I should not focus on thinking too much what's happening outside, and that other drivers want my seat etc.

"I know the fact, but it's very, very simple in the end. Like I've always said, I just really need to focus on the driving and on my performance on track - learning from all the difficult races I had last year. If I can perform every single race on a good level, then there's no problem.

"Then I don't need to think about those things. But I need to deliver; I understand that. For me, it's quite a different feeling going for the second year with the team, because everything last year was quite hectic in the winter. I didn't really have any break - because I was all the time on the phone.

"You can work flat-out for some time, but at some point you need to pay for it - your energy levels can drop a bit and that's when, speaking about Formula 1 and small details, if your performance goes up and down there can be other reasons as well.

"I could see some things I haven't seen before. Small things, but never anything I was thinking 'that's not possible', because always if it's there then it is possible!" Bottas on working with Hamilton

"For me, [I'm] just going to be performing better based on learning from all the difficult moments last year. I learned more last year than I ever thought I would - just the new environment, new people around, new issues and things, made it possible for me to learn much, much more, and that's why I think I can fight for the title this year."

Realising such bold ambition will require Bottas to avoid the troughs in performance that blighted parts of his 2017 campaign.

There were some stunning peaks when the W08 was at its worst, such as his victory over the quicker Ferraris in Russia, and a brilliant qualifying lap in Monaco that fell less than a tenth short of pole on one of Mercedes' least competitive circuits. Considering the car began the season around 10kg overweight, to get so close to the Ferraris was truly mighty. From Monaco to the August break, Bottas was also F1's top-scoring driver.

But there were races in the second half of the year where he looked distinctly second rate - duffed up by Kimi Raikkonen and Daniel Ricciardo in Belgium, as Hamilton fended off Vettel for victory; struggling to get anywhere near Hamilton's pace in Singapore and Malaysia. As the title fight intensified, Bottas tumbled out of contention.

Although Bottas finished his season strongly, with two poles then victory in the Abu Dhabi season finale, there were points during the championship run-in where it looked as though Hamilton could do things with the car that Bottas found impossible. Sometimes, drivers reach a personal limit and discover their team-mates can do things they themselves simply cannot.

There were moments during last season where Bottas seriously doubted himself - where "sometimes I had no idea what was happening" - but he has spent the winter forensically analysing every one of his races from last season, to discover how to eliminate his weaknesses and come out swinging this year.

Bottas feels there is nothing in Hamilton's data that cannot be achieved for himself, and reckons the extra experience gained from working with his new team over the past 12 months will make it much easier for him to take care of the small details concerning car set-up and driving technique necessary to carry the fight to his illustrious team-mate.

"I could see some things on driving that I haven't seen before - how to manipulate the car," says Bottas of Hamilton. "Small things, but never anything I was thinking 'that's not possible', because always if it's there then it is possible! It's up to me to break it down and eventually get there. Lewis's strength is that he can be on the pace very quickly - the first lap of the weekend. He gets to that good level quite quickly.

"For me, there were many cases of some problematic corners with that car, because it was behaving quite differently mechanically to the Williams. This car had to be driven quite differently to be quick with it. That took some time for me to work out - just seeing some corners, some tracks, what Lewis was doing with the car was actually making the car work better mechanically."

Hamilton's greater experience and standing within Mercedes surely makes it easier for him to tread the fine line between adapting his own methods to suit the car, while fighting for technical changes when he feels they are needed. As Stoffel Vandoorne found out at McLaren last year, it's easy to get browbeaten by engineers and taken down a theoretically 'ideal' path that won't necessarily work for the individual driver in reality.

Racing is about finding a working compromise - something engineers, as problem solvers, are instinctively reluctant to do, and drivers, clouded by necessary self-belief, are instinctively reluctant to admit they need. With a year under his belt at Mercedes, Bottas should be better able to find his voice, and better judge when to concede ground and when to fight his corner.

"We went through the whole year with the team, after Abu Dhabi, and the races where I had issues we made lines and pinpointed it was because of this, this and this," Bottas explains. "The races, conditions, set-up issues where I struggled, for sure I learned massively from every single problematic race. It's all about just working on those issues and being better next time.

"Also, the car definitely wasn't easy in places, and that made the up and down sometimes look more. If you dropped out of the window with the set-up, it was very sensitive sometimes, the performance. If you couldn't drive it with the theoretical best set-up, if I had to go in another direction, it was just really going way off.

"Everything I've seen with the development path of the new car looks to the right direction for me. Hopefully, it will be a bit easier to manage and less of a diva. For sure, it's going to help Lewis as well, but especially for me, the races where I struggled, hopefully there won't be those kind of races anymore."

Bottas acknowledges the important mental boost he gained from beating Hamilton to victory in a straight fight to win the final race of last season. This year is not only about carrying that momentum forward, but it is partly about that - putting Hamilton under more and sustained pressure without combusting a healthy working relationship that has helped Mercedes draw a line under the acrimony that defined Rosberg and Hamilton's time together.

"It's going to be easier to negotiate if I win many races. If the performance is not there then it's more difficult, and for sure there's many drivers that want to be in this seat" Bottas on his Mercedes future

Wolff has spoken openly of how much healthier the Mercedes environment has become with Bottas paired alongside Hamilton, and how they each played a key role in working together to turn things around for the team after a difficult start to 2017. The challenge is maintaining that dynamic should Bottas become a proper threat to Hamilton, rather than an occasional nuisance.

"I think good, healthy team-mate competition is always good," argues Bottas. "We both hate losing. We've spoken about it - that when we're on the track we just want to be the best drivers out there.

"But since the very beginning we also knew that we need also to be able to work as a team, so we could really share everything, and I can't see that changing.

"Honestly, even if I'm performing better than last year, I can't see much of an issue. I don't see why we couldn't work together with the team, because last year everything went so well - even in the races where I was on pole or I won, we could still speak very openly afterwards about everything.

"I've never really had any issues with any team-mate. I've always been able to work together. People are different - some can work together; some not. That's just how it goes, like in any sport or business it's the same - some people just can't work together.

"It's very natural for me - I'm a team player. Of course, the only thing I want to do is to win, but still I can work as a team. We've never had to talk about it - how the team should work together - because since day one with Lewis it's been very good."

But the period of grace is over for Bottas. Now, the serious work begins. He must juggle his personal ambition with Mercedes' requirement for totally transparent team play. He must work out how to raise his own game against one of the very best drivers F1 has ever seen, while dealing with the mental pressure of being guaranteed only one more year in the seat everyone with serious ambitions surely wants to occupy.

With drivers of the calibre of Ricciardo coming onto the market this year, and Mercedes junior Esteban Ocon making serious waves with customer team Force India, Bottas knows he is very much on the bubble. He has zero security, so must drive for his life.

"I'm confident that it's going to be a good year," he says. "That's my mindset and hopefully I don't need to worry about those things. I just need to win a lot of races - it's quite simple in the end.

"I have no problem with the contract stuff - I like to speak directly with the team face to face. During the whole of last year we could really speak openly. I don't find it too stressful or anything.

"For me, it's going to be easier to negotiate if I win many races. If the performance is not there then it's more difficult, and for sure there's many drivers that want to be in this seat. I wouldn't choose any other seat in the whole sport."

Bottas will be front and centre this year in the battle for F1's most coveted cockpit. The onus is very much on him to ensure Wolff has no reason to field a fresh host of phone calls over the next 12 months.