How Hamilton won a race he seemed to have lost

The Spanish Grand Prix was always likely to be an acid test of whether Mercedes and Ferrari really can go toe-to-toe throughout the rest of the 2017 Formula 1 world championship.

Barcelona is the circuit for testing the veracity of major aerodynamic upgrades - stretching F1 cars to their limits, exposing any weaknesses, and bringing clearer resolution to the competitive picture.

This picture has been a delicate blend of silver and red over the first quarter of the season, with Mercedes holding a narrow edge in qualifying (when it can get the Pirelli tyres working properly) and Ferrari possessing a more driveable and consistent car that has generally been slightly faster over a race distance.

Mercedes brought a massive upgrade package to Spain and F1 held its collective breath. Would all these obvious component changes, plus the addition of a new and more reliable engine, upset the delicate equilibrium of the thrilling 2017 title fight by lifting Mercedes clear of Ferrari at the front?

Or would Ferrari's subtler alterations maintain the prevailing balance of power between these two F1 titans?

As it turned out, things did not change dramatically, though Ferrari arguably had the fastest car in qualifying for the second race in succession - thanks to the second instalment of a two-stage upgrade it began bolting to the SF70H ahead of the last race in Russia.

Lewis Hamilton took pole position, but without a costly mistake under braking for the final chicane in Q3 that honour would have easily fallen to Sebastian Vettel instead.

Ferrari's messy display in Friday practice made race form difficult to predict, but the Scuderia was consistently excellent in this regard over the first four races of the campaign, so there was no obvious reason to expect it to suddenly struggle in Spain.

Fine details continue to make all the difference in what is fast turning into an epic F1 title battle, and although Vettel again had the fastest car on balance, and probably should have won this race, Hamilton's relentless driving, coupled with that upgraded W08 and smart strategy from his team, helped Mercedes turn the tables on Ferrari and transform a losing position into a winning one.

All signs pointed to a Ferrari victory right after the start, with Vettel taking full advantage of developments of the clutch paddle on his Ferrari's steering wheel to jump Hamilton's wheelspinning Mercedes off the grid, immediately making up for that qualifying setback.

"I saw Lewis struggling with wheelspin and so did I," said Vettel. "But I pulled the clutch in immediately and reacted and tried to set off a second launch phase, which worked excellently."

But this reversal of positions at the start also inadvertently made Vettel's life more difficult. From third on the grid, Valtteri Bottas got a much better launch than both Mercedes team-mate Hamilton and Vettel, but found himself hemmed to the inside as the cars swarmed towards Turn 1.

Bottas braked early, keen to avoid rear-ending Vettel's Ferrari, but this allowed the sister Ferrari of Kimi Raikkonen to attack around Bottas's outside through the first right-hander.

With Red Bull's fast-starter Max Verstappen also fancying his chances to Raikkonen's left, there came an inevitable squeeze at the apex. Bottas clipped Raikkonen's right-rear wheel, which bounced the Ferrari into Verstappen.

Bottas survived the contact, but Raikkonen pulled off the track with broken left-front suspension. Verstappen crabbed back to the pits, but broken rear suspension ended his race as well.

Not only did this incident leave Vettel facing the prospect of fighting two Mercedes single-handedly, it also indirectly tricked Ferrari into thinking Mercedes was still suffering from the tyre management problems that have hampered it so heavily in previous races.

BOTTAS'S TIME LOSS TO VETTEL IN STINT ONE

Bottas struggled badly for speed through the first phase of the race on the soft compound, picking up understeer and suffering from an overall lack of grip too, most likely because of that collision. This convinced Ferrari it would be difficult for Hamilton to hang on to the tyres as well.

Hamilton worked hard to stay within 2.5 seconds of Vettel through the first stint, and Ferrari called Vettel into the pits for the first time at the end of lap 14 of the 66-lap race to deny Mercedes the opportunity to leapfrog Hamilton past Vettel by making an earlier first stop.

Vettel emerged behind Daniel Ricciardo's Red Bull and lost time bottled up behind it through the final sector, but breezed by with the help of DRS on the main straight at the start of lap 16.

"We hoped that Ricciardo would make his life quite difficult but Sebastian's pace was just so much faster and he got past him quite easily," said Mercedes team boss Toto Wolff.

"And from then on we were on the back foot. There wasn't really a lot to do, so we tried to extend the stint and hopefully towards the end of the race have a better tyre."

But there was something else Mercedes could do - use the struggling Bottas to delay Vettel and buy Hamilton valuable time.

Hamilton made his own first stop at the end of lap 21, Mercedes switching him to the slower medium compound to offset strategically against Ferrari, which had put Vettel back on soft tyres for his second stint.

Bottas was instructed to extend his difficult first stint on the soft compound and by Turn 10 of the 22nd lap Vettel found his charge halted by Bottas's slow-going Mercedes.

Vettel tried to pass into Turn 1 at the start of lap 24, but Bottas defended the inside and Vettel's Ferrari bucked underneath him as he tucked back in behind the Mercedes through Turn 2.

Vettel regrouped and, despite a lock-up under braking for Turn 10, managed to get close enough to take another crack with the aid of DRS at the start of the next lap. Vettel sold Bottas two dummies by feinting to the inside then the outside, before diving back inside the Mercedes approaching the braking zone for Turn 1.

"He was all over the place with his tyres so they used him a bit to block me," Vettel said.

"He still somehow managed to get a decent exit [from corners] so I didn't quite make it the first time around. The second time I thought 'now I have to find some way, even if it's over the grass'.

"I faked it on the inside, went back on the outside and then on the inside to surprise him, which worked, but I nearly lost the car because I had DRS open and it was quite an aggressive move on the steering wheel."

Vettel's cut across the grass added dramatic effect in a move that was reminiscent of Nigel Mansell's famous pass of Nelson Piquet for the lead of the 1987 British Grand Prix at Silverstone.

Vettel had lost four seconds to Hamilton trying to fight his way past the second Mercedes, but began to stretch his legs again once clear.

Mercedes told Hamilton he needed to match Vettel's pace and wait for Vettel's tyres to go off, but Hamilton suggested that wouldn't be possible on the slower medium compound.

HAMILTON STRUGGLES TO MATCH VETTEL IN STINT TWO

At this stage, with Hamilton trailing by almost eight seconds, it looked as though Mercedes' only hope of upsetting Vettel was to use the softer tyre to attack at the end of the race. But then Stoffel Vandoorne broke his McLaren-Honda's front suspension by bouncing off Felipe Massa's Williams at Turn 1 while the leaders were midway around their 34th lap.

Officials neutralised the race with a virtual safety car and Mercedes sensed a chance to seize strategic advantage. Many of the midfield cars immediately opted to make a second pitstop under safety car conditions, but Mercedes waited until the end of lap 36 to call Hamilton in, making an educated guess that the VSC period was about to end and realising that pitting just beforehand would leave Ferrari no time to respond in kind.

"At a certain stage we planned to do the opposite to Sebastian and the magic call was the one to take the pitstop at a time when it looked like the VSC would end soon," explained Wolff.

"We timed it perfectly. I really take my hat off to James [Vowles] and his group of strategists."

By the time Ferrari could respond the race was back under way properly. Vettel's in-lap began while the race was still under VSC. This certainly cost him time - around four seconds - at the start of lap 37, but that wouldn't have made the difference had Hamilton not also taken extra chunks out of the Ferrari by blitzing it through the second and third sectors while Vettel headed for the pits.

Vettel's stop at the end of lap 37 was decent enough, but the time lost through the transition from VSC to racing again meant he emerged side-by-side with Hamilton approaching Turn 1.

Hamilton attempted to sweep around his rival's outside, but was squeezed off the road before the entry to Turn 2 as Vettel defended aggressively.

"I wanted to stay ahead but I was just guessing on the brake point," said Vettel, whose tyres were naturally colder than Hamilton's.

"It worked, but there was no room for him. He reacted well, because he avoided the contact. It was really close."

Hamilton sounded perturbed by the incident over team radio, calling Vettel's move "dangerous" in the heat of the moment, but he reconsidered after the race.

"The respect stays the same," Hamilton said. "I think he was tough and hard, just to the edge and no more. I think if he'd hit me that would have been a bit different."

This moment presented Vettel with the chance to break away and seal victory. But although the medium tyre performed much better on Sunday than everyone expected, it was still too slow for Vettel to drop the Mercedes, so Hamilton homed back in on his target.

Vettel defended position successfully at Turn 1 on lap 39 and Hamilton had a couple of tentative looks down the Ferrari's inside on laps 41 and 42, before finally managing to breeze past with DRS open at the start of lap 44.

Vettel bemoaned the fact he had "no chance" to defend as Hamilton's Mercedes stormed past "like a train", and one wonders, given that Raikkonen found it impossible to pass Verstappen for the lead of last year's Spanish GP, if Hamilton would have overtaken Vettel without the FIA's decision to extend the DRS zone on the main straight by 100 metres ahead of this year's race.

"For sure it would've been harder but still possible," reckoned Hamilton. "I think I went past Seb at the end of the pitlane and right by the exit, not far past that.

"The engineers said it was between four and five metres difference that 100 metres gives you - something like that. All it meant was that the pass would have been a few metres down the road.

"[The move] was still a good 200 metres to the turn. Usually it's so hard to overtake here, [so] they did a good job. In the past we've had DRS too late, so people just follow and follow and follow."

Once into the lead Hamilton was asked to build a buffer to counter any possible attempt by Ferrari at 'plan C' - which dictated bringing Vettel in for a third stop, fitting soft tyres and trying to hunt Hamilton down over the final 22 laps.

"We tried to have a pitstop gap of two and a half seconds to be able to react," explained Wolff. "It was balancing on the knife edge, as you want the gap to avoid the undercut but you also need to be able to make the tyres last 32 laps."

It took Hamilton until the end of lap 52 to build a margin of more than 2.5s over Vettel, but given Ferrari was not convinced Hamilton could make the flag without a further stop, owing to Bottas's earlier struggles, it elected to leave Vettel out.

That meant Vettel's only remaining chance of winning the race was to see Hamilton's tyres fall apart before the flag.

HAMILTON EDGES CLEAR IN THE FINAL STINT

As it turned out, Hamilton's fears his rear tyres might overheat proved unfounded. He set the fastest lap of the race with two to go and kept Vettel at arm's length to the finish, scoring a second victory of the season that narrowed Vettel's championship lead to just six points.

Hamilton suggested Mercedes' upgrades had allowed him to perform more consistently through the race distance, but this impression is offset by the fact Mercedes has performed well on the soft compound since the first race in Australia.

It would also have been interesting to see how Vettel fared without that interference from Bottas and the virtual safety car period. Adding the four seconds Vettel lost under VSC to the four he lost fighting Bottas swings the race back to him by 4.5s, but perhaps Hamilton would always have found a way past by being on the quicker tyre at the end.

Regardless, Hamilton certainly knew he'd been involved in a real battle once again, pushing so hard that he was literally breathless inside the car.

"I was very much on the edge," Hamilton admitted. "I was pushing. I couldn't push anymore.

"What I loved about the battle and racing with Vettel is: I love tennis, and watching Djokovic and Federer in the finals, and I really admire the consistency - every hit of that ball, one misplaced shot can mean the game and I admire the concentration. It's awesome.

"Today I felt I had that battle. That's how racing should be."