Serena 'a different story' on men's tour

Tennis legend John McEnroe says that while he has great respect for Serena Williams as the best player of her gender, the 23-time Grand Slam winner would be the 700th-ranked player on the men's tour.

Speaking as part of a tour to promote his new book But Seriously, McEnroe said he would place Williams "like No 700 in the world" on the men's circuit.

"Best female player ever - no question. But if she had to just play the circuit - the men's circuit - that would be an entirely different story," McEnroe said in New York on the weekend.