John McEnroe has described Serena Williams as ‘a global superstar and the greatest player that ever lived’ in a glowing tribute.

Williams has just one more tournament left in her glittering career, with her planning to hang up her rackets after the US Open.

She will retire as the leading women’s Grand Slam winner in the Open Era, but McEnroe believes her legacy stretches way beyond tennis.

“You can look at the accomplishments, she has the Grand Slam victories,” McEnroe said. “The way that she moves the needle when she plays, it’s like Tiger Woods and golf. When she plays, it’s a whole different story.

“Off the court, I don’t know [her] as well, I know that she’s had a lot of difficulties in her life that she talks about in her own documentaries, but she has come out the other end as this icon, global superstar.

“Her story alone, what she represents as someone who’s an African-American girl who came from a tough situation, and became the greatest player that ever lived.

“What that represents for us, and maybe around the world, is an opportunity that it can happen to anyone potentially.”

Serena Williams has won just one match since returning to the WTA Tour after a year’s absence at Wimbledon.

There are fears, therefore, that she will suffer a low-key early exit at the US Open. However, McEnroe says no one should be writing her off.

“Hopefully she’ll enjoy it,” he said. “Serena is like Roger [Federer] – she’s not going there to lose first round.

“She’s played four matches [recently] and lost three of them, so that’s not what Serena wants. With all due respect to Cincinnati and Toronto, she wants to try to do something at the [US] Open. That’s what matters.

“I think that she realised, ‘look, I’ve got to get out in the court, feel it, go through those emotions that you feel on a court so that by the time I get to New York, I’ll be at least somewhat comfortable with where I’m at, and I can do my thing’.

“The younger players are sticking with her now thinking ‘maybe she’s not moving quite as well, now the pressure is not quite the same’. So that’s something she’s going to have to overcome as well as being consistently in points.

“But the bottom line is that people are going to be pulling for her big time. She will be in the night matches and should probably play night every time as long as she’s in the tournament – it would be nice to see her make some type of nice run.”