De la Rosa says Raikkonen the main rival

Raikkonen, who moved from McLaren to Ferrari at the end of last year, is currently tied at the top of the standings with McLaren drivers Fernando Alonso and Lewis Hamilton. Brazilian Massa, winner of the last race in Bahrain, is five points behind.

Finn Raikkonen has failed to dominate his Ferrari teammate so far, and many pundits believes Massa is the favourite to win the title.

De la Rosa, however, reckons Raikkonen will only get stronger as the season progresses.

"Always Raikkonen," said de la Rosa when asked who will be McLaren's main rival. "He's very fast. He'll get stronger at Ferrari and, over 17 races, he is the main rival."

McLaren are currently leading both championships, despite the general impression that Ferrari have the fastest car.

De la Rosa says his team, who have won one race to Ferrari's two so far, will go for victory at this weekend's Spanish Grand Prix, although he admits he is still unsure about the Italian squad's form following last week's test.

"At McLaren we do everything to win and we don't want to show up without options, we'll go for victory," the McLaren drive told Spanish daily AS. "Alonso has won one race out of three and we are not going to back off.

"But we can't be sure about what's going to happen on Sunday, because we only know what we have done.

"The tests have gone well, we have improved the car, especially over long runs, but Ferrari too, so we'll have to wait until the race. During testing in Sepang we were also behind and then we won."