Trying to win tournaments I've never won before is a huge motivation, but I'm not trying to compete with Stan Wawrinka in terms of the numbers.
I know Stan and I have both won three Grand Slams but I don't compare myself with other players in that sense. It's not what I'm playing for.
Over the last few years Stan has played great in the Slams, he's been very consistent.
In the US Open final last year he definitely deserved to win. I also think when he played the French Open final here with Novak Djokovic, he played extremely well.