Mercedes GP team principal Ross Brawn has admitted that, while he is still friends with Jenson Button, there are 'no friends on the racetrack' and the Brackley-based team is fully focused on beating its former driver during the 2010 F1 season.
Button clinched his maiden title for the team last season – then under the Brawn GP banner – but elected to move to McLaren for 2010 to form an all-British 'superteam' alongside Lewis Hamilton.
So far, the move has paid dividends for Button, who has won two of the opening four races to lead the drivers' championship ahead of Nico Rosberg – who came in to fill one of the vacant seats at Mercedes after Rubens Barrichello also moved on at the end of last season.
While admitting he understood why Button had elected to move to pastures new for the season ahead, Brawn said he was still disappointed that the Briton had elected to switch teams and said Mercedes was fully focused on showing the defending champion that he should have remained where he was.
"I was disappointed Jenson left," he said in an interview with The Sun
. "He felt people were of the opinion he only won the world championship because he had the best car. So he left us to show them he could do it again elsewhere.
"We are still friends. We were on the same flight back from Malaysia and we had a good chat. But on the racetrack it is different. There are no friends on the racetrack. Jenson was a fabulous member of our team last year but now he is the history and we have to beat him.
"He also wanted to prove himself at McLaren against the guy who is probably the fastest and most naturally talented in motor racing - Lewis Hamilton. He's set himself a massive challenge and he is doing very well so far."