Jenson Button says his years at McLaren alongside Lewis Hamilton produced the most satisfying races in his 16-year career in F1.
Button and Hamilton raced together at the Woking-based outfit between 2010 and 2012, and while neither won the championship during the three-year period, they delivered seventeen race wins to the British team.
The pair enjoyed a relatively good relationship during their time together, but their rivalry was fierce and intense.
"Our relationship was interesting," Button. told Sky Sports.
"Because I came from Brawn, where I won the world championship in 2009 - and he won the previous world championship in 2008, with McLaren.
"I moved to his team, if you like, so I walked in the door looking for that challenge of racing against Lewis Hamilton.
"Both British, racing for a British team, both world champions, fresh new world champions, so it put a lot of pressure on us and that made it fun, I really enjoyed that challenge."
Button admits that at his best, Hamilton was out of his reach, at least in terms of sheer speed.
"He is unbelievably quick and, over one lap, he is the quickest guy I think that has ever driven a Formula One car," says the 2009 world champion.
"In a race, I could challenge him, and we could race for wins.
"Over those three years we won a lot and some of the races I did win were the best races in my career, because I had to beat Lewis to achieve them."