Kamui Kobayashi said a problem with his Sauber's anti-stall system was the main reason why his home grand prix went so wrong at Suzuka today.
The Japanese driver had started a career-best seventh, but lost five places off the line. He struggled to make progress through the field, and trying to hang on to one set of tyres from the mid-race safety car period to the finish did not pay off.
"It was a tricky race for me," Kobayashi admitted after finishing 13th. "At the start when I released the clutch the car suddenly was in anti-stall mode, and that was why I lost five positions straight away.
"I tried to fight other cars then but overtaking wasn't as easy as it was here last year. Then the safety car came out in what was a bad moment for our strategy.
"I did my second stop when the safety car was out, we changed from the soft to the medium compound and with those tires I then had to go to the end of the race – 29 laps. In the end they were just so bad that I couldn't defend my position anymore. Anyway, I had a good qualifying here and the car's performance in the race has definitely improved, so we will keep pushing at the remaining races."
Team boss Peter Sauber expressed his sympathy for Kobayashi.
"Everybody in the team hoped Kamui could score a good result in his home grand prix," said Sauber. "He would have deserved that after his strong qualifying performance, but then things went wrong at the start. He lost a lot of positions, and his aggressive strategy didn't work as a result of that."
Sauber still scored in the race, thanks to Sergio Perez's drive from 17th on the grid to eighth on a two-stop strategy.
"Sergio drove a brilliant race," said Sauber. "Starting from 17th and finishing eighth says it all. He was aggressive and consistent at the same time. His result also proves that we made a clear step forward with our car, which is important for the upcoming races."