In such a competitive season, Jenson Button says McLaren can only judge itself on the last race despite appearing to have a strong car.

14538 - 'We're as good as our last race' - Button

Having locked out the front row in the opening two races, McLaren struggled in Bahrain with Button retiring and Lewis Hamilton finishing eighth. It was a surprising lack of pace coming straight after a double podium finish in China, and Button admitted that he wasn't sure why there had been such a drop-off so was unable to predict if the team would be competitive in the Spanish Grand Prix.

"I think we've got a good car, I think we proved that at the first race and also in Shanghai we were very quick," he said. "But no I wouldn't say it's the quickest car. If you look at the last race it obviously wasn't the perfect weekend for us but we basically weren't fast. The Lotus' and the Red Bull's were a second quicker than us. I don't understand why and I'm sure nobody else in Formula One understands why, it's such a change around!

"But I don't think that they have a car that is a second quicker than us now, I think it's circuit dependent and I also think that the conditions make a big difference. I know we always talk about tyres but I think the conditions make a big difference to whether you can get the tyres working on a certain car.

"So it's very tricky at the moment to understand who's quick. You'd say in Melbourne and China it was us and Mercedes, and the last race it was Lotus and Red Bull. I've never been involved in a season when there's so many teams fighting for victories at different circuits so I wouldn't say that our car is standout compared to the competitors, and we all say that we're as good as our last race so you would say that the Lotus and the Red Bull are the cars to beat here in Barcelona. But who knows?"

Button also said that he hoped the new front nose would give some extra performance but admitted he'd have to analyse it during Friday practice first.

"We'll see. It's not quite as pretty - but that is if you like sticking up noses or not! We'll try it in the morning; we'll do back-to-back [comparisons], do some more aero work, but it's the sort of thing that if the balance requires it then it's good to have. So it's a good step and hopefully we'll be in the area with the car that we can use that this weekend."