McEnroe ranks Serena 700th on men's tour
Tennis legend John McEnroe says while he has great respect for Serena Williams as the best of her gender, the 23-time Grand Slam winner would be the 700th-ranked player in the men's game.
Speaking as part of a tour to promote his new book "But Seriously", McEnroe said he would place Williams "like 700 in the world" on the men's circuit.
McEnroe told American broadcaster National Public Radio: "Best female player ever - no question. If she had to just play the circuit - the men's circuit - that would be an entirely different story."
The seven-time Major winner said the best thing Williams would have going for her on the men's tour would be her mental strength.
"The reality of what would happen on a given day is Serena could beat some players, I believe, because she is so incredibly strong mentally."
He also said her rivals would crack under pressure.
"She could overcome some situations where players would choke because she's been in it so many times, so many situations at Wimbledon, the US Open, et cetera," he said.
Williams became the oldest woman to win a Grand Slam when she claimed the 2015 Wimbledon title at age 33.
The Los Angeles native has 23 Grand Slam singles crowns and 14 Major doubles titles.
The ATP Tour rankings only features 500 players.
Andy Murray is No. 1 in the world while Temur Ismailov of Uzbekistan holds down the 500th spot.