John McEnroe on Serena Williams

Serena has said before that she wouldn't want to play a man (again) because the game for women and men is totally different.

She, and her sister Venus, did play a 203th ranked male tennis player, Karsten Braasch, in the past and they both lost badly against him, despite him being over a decade older and drinking beer and smoking cigarettes during the match. I don't think she would be down to a 700th player on the men's circuit, though, even though I know nothing about tennis.