Why nobody will beat Red Bull in Spain

'The question is not when he's gonna stop, but who's gonna stop him.'

The quote is from the cult 1970s film Vanishing Point, but it could just as easily be about Sebastian Vettel's 2011 title campaign. While everyone has been very excited by all the overtaking in the first four races, Vettel has effectively led every lap apart from those last few in China. His other races have fallen into an identical pattern: win pole, lead away, get enough of a gap to allow him to respond to his pursuer's pitstop without losing the place, control the gap from there with enough in hand to keep himself out of DRS-trigger reach.

In that sense, his task has been relatively simple. Not easy - it takes huge focus and talent to consistently exploit even the fastest car - but straightforward in a way that his pursuers' races could never be. If only someone could get ahead of him at the start, prevent that RB7 from stretching its legs, imprison it behind a slower car.

That's clearly the way Jenson Button was thinking when he said of McLaren's prospects here in Spain: "Even if they qualify half a second in front of us, there's a long straight down to turn one. If you can get them into there, then the race is anyone's; it's no longer as straightforward as saying the quickest car wins."

The Red Bull is still the quickest car. Lewis Hamilton getting within 0.1s of Mark Webber's fastest time in FP2 conforms to the pattern we've seen so often this season. The full extent of Red Bull's pace is rarely explicit on Friday and if Webber can do a 1m22.4s lap on Friday afternoon, who's to say Vettel can't get into the 21s in qualifying?

The underlying performance comparison of Red Bull to McLaren was probably more accurately reflected in the long runs at the end of the session after the headline-grabbing qualifying simulations had been done. There, we saw Vettel do a 14-lap run on the soft tyre that began in the 1m28s and ended in the 1m30s. Button did a similar-length run beginning in the 30s and stayed at or close to that throughout. Webber did a slightly shorter run in the 29s pretty much all the way, the reducing fuel weight giving him lap time at about the same rate that the degrading tyres were taking it off him. It all implied that while the two cars had similar level of degradation, the Red Bull was up to a second a lap faster.

So to beat Red Bull, it looks like McLaren would indeed need to beat it into the first corner, then make the smart strategy calls. The new (harder) hard tyre is a full 2s per lap slower than the soft and it would appear that this has swerved the favoured strategy back to a choice between two and three stops rather than the three or four we saw in Turkey.

Button says the run to turn one could help McLaren © LAT

The Red Bulls and McLarens both showed the soft could do up to 14 laps. It degrades faster than the hard, but only by around 0.1s per lap - and therefore the crossover time where the two tyres would be doing the same lap time would be around 20 laps. Because this is longer than is required by the stint length of a three-stop race - which would be expected to be faster than two-stopping - the hard will likely only go on for the final stint.

Pirelli's intention in introducing the harder hard was to prevent the three or four stop strategy becoming the standard default. The new tyre was supposed to bring a more finely-poised balance between which was the better race tyre between soft and hard. To do this it needed to be around 1.5s slower than the soft on a single lap but good for an extra 10 laps or so. Whilst it can do the extra 10 laps, it's proved significantly more than 1.5s slower - and so the equation hasn't really worked as intended.

"We don't know yet why the gap is as big as it is," said Pirelli's Paul Hembery. "When we tested this tyre in practice at Istanbul and China - and two weeks ago here, the gap was more like 1.5s."

The teams were finding on Friday that the hard changed the balance of the cars much more towards oversteer than had been the case before - and that's probably where the extra 0.5s deficit has appeared from. It's possible that as the track surface evolves over the weekend, the picture will change more towards what was seen in testing, but for the moment the hard is the unfavoured tyre.

What will be crucial in McLaren's attempt to beat the car that's yet to be beaten to pole this year is having the same number of soft tyres available.

To do that it cannot afford to use a set of softs in Q1. This may sound dangerous, especially given what happened to Webber in China, but it's comfortably feasible. FP2 showed Red Bull and McLaren almost 4s faster than the Lotus - which is around where the Q1 cut-off will be. Even with tyres that are 2s slower, they still therefore have a theoretical 2s cushion.

We've seen so far this season that Ferrari's race pace is very strong, but there's no indication in Spain that its latest upgrades - floor and wings - have found it the single-lap pace it lacks. It's going to be difficult - even for Fernando Alonso - to get in front of the Red Bulls if he's starting from his habitual third row slot.

The Mercedes appears to have slipped in competitiveness relative to Turkey and China, its upgrades not seeming to find as much time as those of McLaren and Ferrari. There's a lot of work to do if it's to repeat its recent trick of being the fastest non-Red Bull in qualifying.

But if we're looking at who's gonna stop him, what about looking inside the team? What about Webber? He's been behind Vettel in every single lap of the season to date, has not out-qualified him since Spa last year and does not gel as well with the Pirellis as Seb. But he's a fierce competitor - and he needs no reminding of the breakthrough he made in dominating here last year after an indifferent start to his season. In fact, difficult though his season has been so far, it's still way better than last year's. In the four 2011 races to date he's finished fifth, fourth, third and second.