Roger Federer vs. Serena Williams. Who wins?
We got Fed outside UNIQLO in NYC on Wednesday and asked him straight-up.
Obviously, Federer told us he's betting on himself ... but it begs the question, could Serena -- the greatest female tennis player of all time -- REALLY compete with Fed in a serious tennis showdown?
Remember ... Serena's been engulfed in this Battle of the Sexes subject for years. John McEnroe says he was once offered $1 MILLION by Donald Trump to do battle with her.