The American star, who last tasted Grand Slam success at the Australian Open in 2017, still finds herself one Major title behind the record of 24 held by Court.
Williams may end her career without matching the record of the Australian, but Mouratoglou believes her legacy as the greatest player ever has already been secured.
“Margaret Court was playing at a time when three-quarters didn’t even go to Australia (for the Australian Open), where tennis was an amateur sport, when the draws were 16 players,” said Mouratoglou.
“I don’t mean to disrespect Margaret Court, but it’s another era. Yes, it would be better if Serena broke her record but, if she doesn’t, she will still be the greatest player of all time.”
Williams will be 40 tomorrow and has not played a competitive match since Wimbledon three months ago.
Mouratoglou insisted she still ‘has it’ to win another championship.
“The question is how much she wants it and what is she willing to do to get there?,” he said.
“Since she had her daughter, it’s harder. She has a lot of trouble not putting her life as a mother before her life as a player which is completely understandable.”