Sergio Perez thinks there is nothing he can do to end the scepticism over whether he is the right man to replace Lewis Hamilton at McLaren until he races for the team.
The Mexican has not scored a single point for Sauber since he signed for McLaren, and a spate of on-track incidents have left some questioning the wisdom of the Woking team's choice.
"Even if I won all the last races, there will always be question marks," he said when asked by AUTOSPORT about the recent criticism.
"I am going to the best team next year, so there will always be a question mark until I constantly deliver in a McLaren. This doesn't bother me.
"My main focus is to give 100 per cent here, every lap, on every single occasion I drive at Sauber and I will keep doing this."
Perez insists that his focus has not been affected by his switch to McLaren, even though his form has trailed off since it was announced.
Reflecting on recent races, Perez said: "It has been a bit up and down. I spoke to Charlie [Whiting] after my accident in Abu Dhabi and he agrees it was not my fault.
"I still think if I had my chance again I would keep doing the same, because I did the right thing there to try and get past [Paul] di Resta. Otherwise I would spend the whole race behind him.
"Maybe I did the mistake when I tried to overtake Hamilton [in Japan], but I think in some races I have put the car in a much better position than we thought.
"So I feel I am doing a good job but, for some reason, we don't manage to get the final result. I am happy though and I will keep giving my team 100 per cent.
"It would be unfair for my team if I signed a contract and then didn't keep pushing until the last lap of the season."
McLaren team principal Martin Whitmarsh has fielded a host of questions about Perez's suitability for McLaren in recent weeks, but he insists the partnership can work.
Speaking after another point-less outing for Perez in America, Whitmarsh said: "He has a lot to learn and we have got a hard winter ahead of us with him. But I am looking forward to working with him next year."