Serena Williams has just shut down a former tennis great with one ferocious serve.

Tennis world number four Serena Williams has firmly hit back at John McEnroe after the former sporting great suggested she would be “like No. 700 in the world” if forced to compete against men.

“Dear John, I adore and respect you but please please keep me out of your statements that are not factually based,” the 35-year-old tweeted on Monday night.

McEnroe made his controversial comments over the weekend, telling NPR that while he considers Williams to be an incredible player that could beat some male competitors purely through her mental strength, if she were forced to play the men's tennis circuit - which comprises of the best of five sets as opposed to the women's best of three - "that would be an entirely different story."

McEnroe also said that while there may one day be a female sportsperson that is better than a man, he's yet to witness it.

"I just haven't seen it in any other sport, and I haven't seen it in tennis. I suppose anything's possible at some stage," McEnroe said.

Not giving time or energy to the comments though, Williams, who has won 23 grand slam titles, added one final tweet - ending with three sassy words that have us fist-pumping.

Listen: Serena Williams does not and will not apologise for her success. Post continues... 

Interestingly, McEnroe's weekend comments contradict previous statements made about Williams.

In 2015, the former champ and now commentator called Williams "arguably the greatest athlete of the last 100 years."

While watching Williams' historic US open final in 2012, McEnroe said, "You're watching, to me, the greatest player to ever play the game."

In 2017, Williams won the 2017 Australian Open while pregnant. She and her fiance, Reddit co-founder Alexis Ohanian are expecting their first child together later this year.

Hours after McEnroe made his controversial assessment, Aussie player Nick Kyrgios was also drawn into the fight by Channel 9 presenter and 3AW radio presenter Tony Jones.

“I agree with him [McEnroe] on one point," Jones said on-air. "I think she would beat Nick Kyrgios,” Jones explained, “I say that because she has a power game, there’s no doubt about that. But he [McEnroe] touched on something that is more important, especially when you’re playing something like Nick Kyrgios whose brittle above the shoulders — it’s a mind game as well."

Jones added, “Her mental strength alone would see her get the better of someone like Nick Kyrgios — I’d back her in.”

Kyrgios, who is known for his on-court outbursts, wasn't buying it, though, responding to Jones' comments with a tweet that asked, "If this is the case, Djokovic, Fed & Nadal would struggle against her? Since they all have had a tough match against me?"