Jenson Button said that the KERS problem he suffered during the Abu Dhabi Grand Prix left him uncertain of his McLaren's performance from one lap to the next.
Despite spending most of the race without KERS, Button held off late challenges from Mark Webber's Red Bull and Felipe Massa's Ferrari to take the final spot on the podium behind Lewis Hamilton and Fernando Alonso.
Afterward the 2009 World Champion said that KERS had cut out on a number of occasions during the grand prix, which compromised not only his car's performance, but his own driving as well.
"I'm not sure my pace was entirely there on the soft tire anyway," said Button. "But by lap 13/14, I didn't have any KERS, which wasn't great. In the next stint they [the team] said what I could do to get KERS back, and I got it back, but it only lasted two laps so I had to keep resetting it.
"The problem's not just when you accelerate, but it's under braking, too. You get a certain amount of engine braking from it when it's working, but every time I arrived in a corner I didn't know what to expect.
"I had to fend off Webber and Massa, which was quite interesting without KERS. Coming home third I'm relatively happy."
Button's third place means that he will secure the runner-up spot in the championship by coming home third in Brazil in two weeks.