Serena Williams turns 40 on Sunday with her long-time coach hailing her as the "greatest of all time" and a pioneer of tennis "intimidation".
The American superstar is frustratingly marooned on 23 Grand Slam titles, one short of the all-time record held by Margaret Court.
However, her French coach Patrick Mouratoglou told AFP that her legacy is secure.
"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.
Court, an Australian, won 11 of her Grand Slam titles at her home event.
"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, whose sister Venus, a seven-time major winner, is still playing on tour at 41, won the last of her 23 Slams at the 2017 Australian Open.
It was achieved while she was pregnant with daughter Olympia who was born in September that year.
With former world number one Serena now down at 40 in the rankings, questions have been asked over her future in the sport.
"She still has it. The question is how much she wants it and what is she willing to do to get there?," added her coach.
"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.
"I think that's the main reason she didn't win a Grand Slam. Her family comes first and in order to be able to do great things in one area, that area can't come second.
"She is reflecting and we will see what comes out of it."
Williams has been beaten in her four Grand Slam final appearances since her 2017 Melbourne triumph.
She has not made the championship match at a major since Wimbledon in 2019.
She missed this year's US Open in New York, where she won her first Slam in 1999, with a hamstring injury.
The last of her 73 career titles came in Auckland in January 2020.
