Jenson Button's mid-season slump can be put down to the British driver's failure to cope with the pressure of a World Championship campaign, claims Felipe Massa.
With Button having failed to finish on the podium since the Turkish Grand Prix, the Brawn GP driver is facing a renewed threat from his teammate Rubens Barrichello – with Red Bull Racing's drivers not too far behind either.
Massa, who has watched the title battle unfold at home while he recovers from his Hungarian Grand Prix accident, thinks the title fight is now wide open – and reckons Button will lose out if he does not start handling the pressure better.
"Look at me – I came to Brazil six points behind [Hamilton], and I almost won the championship," Massa said in an interview with The Guardian newspaper on Tuesday. "That was one race. Rubens has five races to close 16 points. It's a big possibility. But it depends on Jenson. If Jenson carries on in this bad way it will help Rubens a lot. In my opinion, Jenson has gone down because of the pressure. It's the only reason.
"At the start of the season everything was nice, everything was easy. He was in a new team winning six out of the first seven races. That's different to fighting hard for the championship. Now he has a different kind of pressure.
"In the earlier races he was almost half a second quicker than some teams. You win the race easy and there is not so much pressure. But now we have races where things are more difficult.
"So for me the pressure has had a big impact on his mind – and he needs to deal with it better. If he does not cope with the pressure he will not win the championship."
When asked for his feelings about which way the title would go, and whether Button could recover, Massa said: "It's difficult to talk about another driver. I know Jenson but I don't know him so well. But I'm hoping for Rubens, of course. He's Brazilian – and he is my friend."