Heidfeld concerned over faster Kubica

The German driver dominated his Polish teammate last year, but Kubica has held the upper hand in the first five races of the 2008.

Kubica has outqualified Heidfeld in all grands prix so far this season, and he has also finished ahead of the German in four of the five races.

Kubica has also given his team their maiden pole position.

Heidfeld admitted on Wednesday that he is finding this year's car harder to drive, although he says that's no excuse.

"I find this year's car is a bit more difficult to drive than last year's," Heidfeld told reporters at Monaco. "But I don't want that to be seen as an excuse because obviously we both have the same car.

"I think the main problem is over one lap, but even in the race is not perfect. That's the way it is and we are obviously trying to improve things. I hope I will get on top of it.

"It is a bit of a concern because I don't like being slower than my teammate and Formula One is my life. So it's not a situation I enjoy being in at the moment. It sometimes can happen in Formula One, but unfortunately it doesn't make it any nicer."

Heidfeld has qualified in ninth place in the last two races and is yet to start higher than fifth.

His qualifying problems have meant his races have been compromised because of the difficulty in overtaking.

The German says, however, that he is not feeling any added pressure ahead of this weekend's race in Monte Carlo, where overtaking is virtually impossible.

"There's no extra pressure, because overtaking is difficult everywhere. Of course here in Monaco is even more so, but it doesn't change anything for me."

The BMW driver is still hopeful his team will be closer to the top after losing some ground in the last race in Turkey.

"I think in the last race we saw that Ferrari were quicker than us and also McLaren was ahead of us more clearly than in the races before," he said.

"Obviously we hope it's going to be different here. We have a lot of new parts on the car, especially on the aero side, but I guess it's similar with the other teams, because this is is incomparable to any other circuit. So we have that we will be closer."