Heidfeld plays down BMW form

Close evaluation of the testing data has indicated that the new F1.07 is quick on both low-fuel single laps and especially on long runs.

And it was their performances in recent testing that led Felipe Massa to single them out as the team to watch last week, as he believes they were ahead of both Ferrari and McLaren.

"The McLaren surely looks fast, but in my opinion the BMW Sauber is the best of all at the moment," Massa told Gazzetta dello Sport.

"I'm saying this by not just looking at the fastest time of this last day, but by seeing their consistency over their long run simulations.

"For me, the BMW Sauber at Valencia was impressive, and at Jerez they've done some very interesting tests too."

Heidfeld has said he is happy that Massa has been so impressed with his team's performances, but believes there is still a long way to go before they can expect good performance for the start of the season.

And in particular he feels that BMW-Sauber still need to make a big step forward with their reliability.

"It is nice to hear other people saying how fast we are but we still do not know really," Heidfeld told autosport.com. "Until Melbourne no one knows what each team is doing.

"I am not surprised those people are saying these things to take off the pressure on them, but really I do not know. Of course I'd rather be in this position than otherwise.

"We have the pace but we still need to work on the reliability. But I know it is easier to work on the reliability on a fast car than the other way."