Am I sexist to think this way?

The big news in the world of tennis today is the announcement that, starting this year, women will be paid an equal amount of prize money as the men at Wimbledon. Perhaps I'm just an ignorant male, but if men play five set matches and women only play three, shouldn't men be paid more? Over the course of an entire tennis tournament like Wimbledon, those potential two extra sets per game can eventually add up to a lot of playing time on the court. It seems the fair thing to do would be to have the women play five sets, too. To pay women the same amount of money for what amounts to less work actually seems to make women look weaker, not stronger, like they can't handle the increased playing time. Maybe someone out there with a better perspective about the difference between male and female athletics can explain this to me.