The seven-time major champion, speaking as part of a tour to promote his new book 'But Seriously', said that while he has great respect for Serena, he would place the 23-time Grand Slam winner "like 700 in the world" on the men's circuit.
The 36-year-old, talked about what she has been going through since giving birth to her daughter, Alexis Olympia, who turns one this September.
American Serena Williams withdrew from the French Open on Monday, shortly before she was due on court to face Maria Sharapova in a much-anticipated fourth round showdown.
World No 1 Serena Williams smashed a racquet and recovered from a set down as she overcame stubborn resistance from Caroline Wozniacki in a semi-final at the WTA Finals last week. It was not the first time the world No 1 abused her playing equipment. Take a look at previous moments when she soaked up her frustration on court by smashing her racket.
Italian tennis ace Francesca Schiavone has said that she regards Serena Williams better than Steffi Graf after she drew within four Grand Slam titles of the former German great's Open-era record.
Venus Williams has always taken her role as big sister to Serena very seriously but never before had she thought a bit of family intuition would end up saving the life of the 13-times Grand Slam champion.
Serena had said on Monday that she "can't wait for the future" as she warmed up for her return to the WTA Tour at the Tie Break Tens exhibition at Madison Square Garden.
Not just because Serena Williams looks capable of landing a 24th Grand Slam title against all the odds having returned from maternity leave and Maria Sharapova is seeking redemption after a 15-month doping ban with a third French Open title.
Her coach Patrick Mouratoglou believes she is now ready to matching Margaret Court's all-time record of 24 Grand Slams.
Maria Sharapova's dreams of a sixth Grand Slam title were ended by Serena Williams and her wrecking ball serve in the Australian Open final on Saturday, but the Russian was adamant she would someday have the American's measure.
Iga Swiatek has been not been at her world-beating best in the months leading up to the U.S. Open but the Pole has both the talent and mentality to lift her game for the final Grand Slam of the year, tennis great Chris Evert said.
SSerena Williams swept past Anastasija Sevastova 6-3, 6-0 on Thursday and into the final of the US Open to sit one win away from a record-equalling 24th Grand Slam title.
Bianca Andreescu, 19, the first Canadian to win a major in the professional era, prevented Serena Williams from equalling Margaret Court's record of 24 Grand Slam singles titles.
After the celebrity pair's first-round Wimbledon win over Andreas Mies and Alexa Guarachi last week, Murray tweeted: "Well that was fun... #SerAndy"
Serena Williams has not won a set in any of the four Grand Slam finals she has reached since returning from maternity leave in September 2017.
Three-times winner Serena Williams moved into the Toronto Open second round after beating Spain's Nuria Parrizas Diaz on Monday
Serena will not be in the US team for the Tokyo Olympics
The 36-year-old has been practising hard on the grass and few would bet against her becoming the first mother to win the title since Evonne Cawley 38 years ago.
Serena will be chasing her seventh grand slam title on Saturday against a 17-year-old who has taken her second Wimbledon by storm.
Separated in age by 25 years, their careers overlapped only briefly and Martina Navratilova, who herself won 18 Grand Slam singles crowns, never faced Serena Williams on a singles court.
Frenchman Adrian Mannarino also quit at two sets apiece against eight-times champion Roger Federer after sliding over on Centre Court and injuring his knee.
Seven-time champion Williams had been bidding to claim a record-equalling 24th Grand Slam crown but made too many errors as Kerber ran out a comfortable winner in the final.
The 23-times grand slam winner made her comeback at Indian Wells in March and has not played since her opening round defeat by Japan's Naomi Osaka at the Miami Open.
Serena Williams will return to the court for the first time since the start of the coronavirus pandemic when she competes at the inaugural edition of the Top Seed Open in Lexington, Kentucky beginning August 10, the WTA said on Thursday.
The players have been allowed out to practise for five hours a day during their quarantine but Djokovic said he had headed to a local park on his first morning in Australia without restrictions.
American tennis ace Serena Williams has pulled out of next week's Madrid Open, saying that she needs more time to prepare for clay-court season.
Sets up Venus tie on return after COVID-19 hiatus at the Top Seed Open.
Halep has struggled for form and fitness since her first-round defeat at the US Open last August and came to Australia on a five-match losing streak and without a coach after long-serving Darren Cahill left for "family reasons".
Serena Williams will be favourite for a fourth French Open title if she survives into the second week, former men's champion Jim Courier believes.
Serena Williams' Australian Open ended with her ankle swollen to the size of a balloon, a spasming back and a quarter-final loss to a young pretender on Wednesday, a two week period that she described as the worst she had experienced at a Grand Slam.
Serena Williams made her first public appearance since the birth of her daughter Alexis Olympia in September, at the Glamour Women of the Year Awards at the Kings Theatre in Brooklyn, New York City.
Serena Williams said on Saturday the COVID-19 outbreak has not only given her a much needed stretch of downtime with her family, it has also turned her into a bit of a "neurotic" and "a recluse" given her past health scares.
Factbox on American Serena Williams, who won her 15th Grand Slam singles title at the US Open on Sunday with a 6-2, 2-6, 7-5 win over Victoria Azarenka of Belarus.
Germany's experienced Angelique Kerber stands in the way of the 36-year-old American and an eighth, and arguably most impressive, All England Club singles crown which would see her match Margaret Court's all-time record of 24 Grand Slam titles.
Serena displayed great mobility to win successive points after long rallies -- one of 21 shots, one of 13 -- and secure what proved to be a decisive break of serve.
If players, pundits and bookmakers are to be believed, Serena Williams has already sewn up her sixth Australian Open title and the other 127 women in the draw may as well pick up their racquets and head home.
The video shows Williams covering her breasts with her hands while singing the global hit song of an Australian Band, The Divinyls.
A factfile on Serena Williams's controversial moments with officials at the US Open following her defeat to Japan's Naomi Osaka in Saturday's final.
After straightening her hair, it was time for nose piercing for Serena Williams.
The glittering career of Russian former World No 1 Maria Sharapova was in tatters after she was given a two-year ban by the International Tennis Federation. Check out the high points in her career...
