McLaren racing director Eric Boullier has no doubt the ailing team will be back in the mix this weekend as Formula One returns to its European stronghold.

Following a positive start to the campaign in Australia, where rookie Kevin Magnussen and Jenson Button were second and third, McLaren have failed to score a point in their last two races.

From believing they had turned a corner after failing to step on to the podium at all last season, the team came off the rails in Bahrain and China.

Clutch problems accounted for both Button and Magnussen in Bahrain, and in China a lack of pace and downforce saw the duo finish a lap down on winner Lewis Hamilton in a miserable 11th and 13th.

Boullier, however, is adamant McLaren are nowhere near as bad as the result at the Shanghai International Circuit suggested.

"We have been lacking downforce, we know this, which has had a direct effect on tyre wear and tyre degradation," said Boullier.

"We know where we have had to address the issues on the car, and we have been working on it.

"Another issue is the range of performance on our car is weather dependent - if it is too hot we are out, too cold we are out.

"That is all because we are missing downforce and we cannot exploit the tyres as easily as Mercedes and Red Bull."

Boullier, however, is convinced the tide will turn, hopefully with Sunday's Spanish Grand Prix at Barcelona's Circuit de Catalunya.

Asked whether his team will be back in the mix, Boullier replied: "Definitely. This is 100 per cent sure.

"What we have seen on the track has been one thing, but back in the factory we know what is going to happen in the next three or four races.

"I know what is going on, that we are on a very good development rate. What we have picked up over the past few weeks is good, very good.

"While not all of the steps we have taken will be in evidence in Barcelona, they mark the start of a fresh push and spirit within the whole organisation."

Now in his fifth year with McLaren, not once over the previous four seasons has Button endured three races in a row without scoring.

The 34-year-old can only hope the team have made progress during the recent mini-break to ensure he avoids such an unwanted feat.

Button said: "For us, it's not simply about bringing new parts to the circuit, it's about understanding and unlocking the car's secrets and using that understanding to take bigger steps with performance.

"We're still at the early stages with our car, and for us it's less about the components we fit to it, and more about the bigger picture - finding a useful direction, gaining trust in our measurements and pushing ahead.

"We all know this team has the capacity to develop a car through a season, so I hope and trust we'll start to push forwards again soon."