Sebastien Buemi admitted he was frustrated with himself for letting both Adrian Sutil and Kamui Kobayashi pass him during the European Grand Prix, even though he still finished eighth for Toro Rosso.
Having gained ground at the start and during the safety car pit stops, Buemi could have taken sixth had he not lost out to Sutil mid-race and then Kobayashi's final-corner dive on fresh tires.
"This was not a very good race as I could have finished sixth, but I made two mistakes, which have cost us four points," said Buemi. "I am happy to be in the points, but disappointed to have missed out on the opportunity to do better.
"As for losing seventh place, I knew Kobayashi was closing very quickly on new tires, and on the penultimate lap I was blocking my front tires a lot. But at the final corner, I did not think he could brake that late and so I am unhappy that I made the mistake and let him pass."
The Swiss driver is among the nine being investigated for potentially returning to the pits too fast during the safety car period. Buemi admitted that it was possible he had exceeded the permitted speed.
"I found it very hard to slow down, as required by the rules, because the safety car arrived very late as we approached the start/finish line," he said. "Let's wait and see what the stewards will say."