Red Bull has pace to upstage the title battle

The emerging pattern developing from recent form in Formula 1 suggests Red Bull is now consistently quick enough on conventional circuits to potentially play a disruptive role in what remains of the championship fight.

Of course it is still the case that if Lewis Hamilton and Nico Rosberg do a good job and are not derailed by technical problems, lost track time, or set-up blind alleys, they should qualify on the front row and win every race from now until the end of the season.

But it's been the case in the past that they could afford to have unclean weekends and still emerge at the head of the pack - such is the competitive advantage Mercedes has enjoyed since V6 hybrid engines arrived in F1 for 2014.

That advantage however is nowhere near as comfortable as it used to be, and generally speaking it is because Red Bull - the team that Mercedes deposed as F1's dominant force - is starting to apply serious pressure.

This weekend's United States Grand Prix is the sixth race since F1's August summer break, and only at Monza's Italian GP has Mercedes totally run away with proceedings.

There, Lewis Hamilton was able to recover easily to second after a poor start from pole position, but Monza is a circuit made up mainly of straights, where all cars run peculiar, low-downforce, aerodynamic packages.

Monza's particular nature allows Mercedes to ram home its residual engine advantage over the pack, by running more downforce than rivals without suffering the same relative penalty of drag.

That equals better braking and cornering stability, without suffering too much relative straightline speed loss, which equals a comfortable lap time advantage over the field.

But other than in that race, Mercedes has not had things all its own way. At Spa, where there is a greater compromise between downforce and drag, Max Verstappen capitalised on Mercedes' difficulties making the super-soft tyre last in baking heat to come close to stealing pole position.

With a better start he might have put Rosberg under pressure in that race. Team-mate Daniel Ricciardo was still quick enough, despite Spa's two long full-throttle drag-race sections, to hold off Hamilton for second as the second Mercedes recovered from a back-of-the-grid start.

And at the last three races - Singapore, Malaysia, and Japan - all held on circuits where a more conventional full downforce set-up is generally run, Red Bull has been very close behind Mercedes, willing and able to capitalise on the slightest slip.

In Singapore Ricciardo split the Mercs to qualify second, and beat Hamilton in the race, hunting down Rosberg late on to the extent he finished within half a second of victory.

In Malaysia, Red Bull was able to match Mercedes over longer runs in practice and Verstappen was applying pressure to leader Hamilton strategically before the reigning champion's engine let go.

Rosberg was spun to the rear of the field by Sebastian Vettel at the first corner, but didn't have enough pace in the car to recover back past either Red Bull. If that same race had occurred two years earlier he probably would have won it.

And in Japan Verstappen was quick enough in the race to prevent Hamilton recovering to second after another poor start. It required another controversial late jink approaching the braking zone for the final chicane, but the Red Bull was nevertheless fast enough to successfully defend position.

Red Bull is now consistently quick enough in the corners, despite the disadvantage of running a Renault engine, that Mercedes must keep a wary eye watching over its shoulder.

In fact, Mercedes doesn't even have to look that far around at present, thanks to Ricciardo's excellent display in Friday practice at Austin.

The Australian impressively split the Mercedes duo, ending up within two tenths of Rosberg's pace-setting time during the qualifying simulation runs on the super-soft tyre.

PURE PACE RANKING
1. Mercedes (Rosberg) 1m37.358s
2. Red Bull (Ricciardo) 1m37.552s
3. Ferrari (Vettel) 1m38.178s
4. Force India (Hulkenberg) 1m38.508s
5. McLaren (Button) 1m38.713s
6. Toro Rosso (Sainz) 1m38.971s
7. Renault (Magnussen) 1m39.159s
8. Sauber (Nasr) 1m39.189s
9. Williams (Bottas) 1m39.197s
10. Haas (Grosjean) 1m39.554s
11. Manor (Ocon) 1m40.086s

Things look even more encouraging for Red Bull over the longer race runs, where Ricciardo was fastest of all on both the super-soft and soft compounds.

Ricciardo's super-soft run was impressively fast and consistent. He was able to maintain a pace that neither his Red Bull team-mate Verstappen nor Rosberg could match. Hamilton got closest in terms of general trend, but over fewer laps and by starting off at a much reduced pace.

On average Ricciardo was over three tenths per lap quicker than Hamilton, and four tenths faster than both Verstappen and Rosberg.

Both Red Bulls showed impressive pace on the soft compound, with Ricciardo fractionally faster on average but Verstappen showing greater consistency over a larger number of consecutive laps.

Rosberg was over half a second per lap down on Ricciardo on average over the course of his long run on this tyre.

No wonder Ricciardo was feeling pretty bullish after what he described as "one of our best Fridays".

"We made some changes between the two sessions, and we look pretty good for now, hopefully we stay like that," he said. "We should have a good race on Sunday if that's the case.

"It's nice to start the weekend on the right foot. There'll be a bit of finetuning as always, but we don't have to search for too much at the moment.

"I think we can still find a bit more. I'm sure Mercedes will probably have a bit more. If we've got the pace we had today against Mercedes then it's going to be a fun race.

"I'm not sure where they are with engines and how conservative they are running, but today we looked good. Let's see what happens over the next 48 hours."

Rosberg complained of "strange oversteer" on his soft tyre run, which explains some of his deficit to Red Bull.

"Friday has been a decent start to the weekend, we've found a good balance in the end," Rosberg reckoned. "The race run was OK - Red Bull are our nearest competitor again.

"It's going to be interesting, because the wind will change 180 degrees [for Saturday], and it transforms the car totally, so maybe what we've learned might not apply and we'll have to start from scratch, so that will be a challenge."

Mercedes may also feel it has a superior bank of knowledge heading into the race, thanks to Hamilton being the only frontrunner to complete a longer run on the medium compound.

Degradation seemed to set in fairly quickly on the super-soft, which suggests it won't be a huge amount of use beyond being the qualifying tyre of choice on Saturday, depending on how much the track improves over the rest of the weekend.

"The hardest tyre is generally the worst tyre and it wasn't that great to be honest," said Hamilton. "I think by lap eight I was starting to match the soft.

"I wasn't comfortable in the second session. We made some changes that made the car better, but some brake setting changes we made were disastrous, so I was struggling to finish a lap without oversteer.

"[Red Bull] are going to be very quick this weekend, it's going to be a challenge. Ricciardo is looking very quick."

Ferrari showed a sudden revival in form last time out at Suzuka, sneaking both cars ahead of Red Bull in qualifying, and showing the sort of form in the race that allowed Vettel to briefly challenge Hamilton and Verstappen for the minor podium positions.

But that revival hasn't continued apace so far in Austin. Both drivers made errors during their qualifying simulations, with Kimi Raikkonen's so bad he ended up slower than both Force Indias and both McLaren-Hondas, which so far look to be the leading midfield contenders, with Toro Rosso and Williams coming more into play over longer runs.

Raikkonen complained about the rear end of the Ferrari on the short runs, and the front end during the longer ones. His super-soft run was over a second per lap slower on average than the Red Bull and Mercedes drivers. On the soft he was 0.131 seconds per lap slower on average than Rosberg.

"It was a difficult Friday," Raikkonen admitted. "We struggled getting the set-up where we wanted, but sometimes it goes like that. It's not a major issue but obviously we have some work to do.

"In the last few races we had tricky Fridays and it's not the best, but we have to work on the set-up and see where we are."

It was a similar story for Vettel, who completed an 11-lap long run on softs, earlier and out of sync with the other frontrunners. His average lap time was nearly 1.3s slower than Rosberg's and over 1.7s down on both Red Bulls.

His super-soft run was better - quicker than all bar Ricciardo in terms of average lap time - but this run came much later and over a smaller number of laps (four) than those of his rivals, so cannot be considered properly representative.

"It was a tough day," he said. "This morning we had a problem with a little wing that failed and came off. We lost some track time and it was a bit costly for the afternoon, because we couldn't really re-balance the car.

"We're a bit on the back foot. I'm not entirely happy with the car balance yet - it's a little bit too nervous all around.

"In general it's a track we like. We didn't have the rhythm yet for a couple of reasons. Some of them I mentioned, some of them I don't want to mention.

"If I trust 100% the car, with some things that I think will be better, then I think qualifying can be very good and able to squeeze hopefully a bit extra."

Mercedes usually has that little bit extra in hand, certainly for qualifying, and we can expect Rosberg and Hamilton to duke it out for pole if they keep their cars on track and don't suffer any unexpected hiccups.

Hamilton was faster through the first sector on the medium compound than he was during his super-soft qualifying run, which is an ominous sign in itself.

But the point is to put the lap together, and Ricciardo is really snapping at Mercedes' heels at a circuit he goes well on. Any mistakes from the leading pair and he will be ready and waiting to pounce. If Verstappen gets his act together we can expect him to be in the mix as well.

This bodes well for 2017, when F1's competitive equation should rebalance further towards aerodynamic prowess and away from pure engine muscle.

Provided Renault can do enough over the winter to put itself in range of Mercedes - Red Bull estimates it needs the sort of 3-5% deficit it had during the latter days of the V8 era - then the 2017 title fight could become more than the one-team, two-horse race we've become accustomed to.

If Ferrari can get things together properly and consistently on the chassis side then it could be a truly epic battle.

Fingers crossed...