John McEnroe has defended Serena Williams for her outburst at the U.S. Open last year and admitted male and female athletes are held to different standards.

During an appearance on Watch What Happens Live with Andy Cohen on Thursday night, the seven-time Grand Slam winner was asked by the host whether he thought women can get called out for something men would get away with.

McEnroe said the suggesting was "accurate" and that it stemmed from holding women and men to different standards.

"I think it's unusual to see that [an incident such as the one Williams was involved in]," he said.

"I guess women are brought up differently. To me, the expectations between male athletes and female athletes are a little bit different.

"But that doesn't mean it should be always that way. I'm willing to allow it to be exactly the same. You can put men and women exactly on the same term, as far as I'm concerned."

The controversy surrounding Williams' outburst at the U.S. Open final in September overshadowed the match itself. The 23-time Grand Slam winner was given three code violations during her straight-sets loss to Naomi Osaka and insulting umpire Carlos Ramos.

She was first given a penalty for on-court coaching, which is prohibited under the rules of the Women's Tennis Association. Williams then smashed her racket on court, which cost her a point and branded Ramos a thief, which ultimately cost her the game.

In the aftermath, the American called out the "double standard" surrounding the way reactions from male and female athletes are perceived. Her stance was strongly supported by Billie Jean King, who won 12 Grand Slam titles and helped set up the WTA and by WTA chief executive Steve Simon.

McEnroe, whose volatile temper and on-court outbursts became legendary during his playing career, was also firmly in Williams' camp.

"I can totally relate to what she was feeling," he said in response to a caller who asked whether the umpire would have behaved differently had Williams' outburst come from a male player.

"It was a bulls**t call, they called her out for coaching when all the other players get coached all the time."

McEnroe then acknowledged Williams deserved her penalty from losing her temper and breaking her racket and suggested she thought her outburst against the umpire was going to be unpunished.

He then suggested the umpire should have simply warned Williams she would be losing a game is her antics carried on, instead of getting involved in a discussion with her.

"I think he went overboard," he explained.

"I didn't like what he did to her. Ultimately it was a lose-lose situation."

Serena Williams argues with umpire Carlos Ramos during her Women's Singles finals match against Naomi Osaka on Day 13 of the 2018 US Open at the USTA Billie Jean King National Tennis Center on September 8, 2018 in New York City. Jaime Lawson/Getty Images for USTA