Jo-Wilfried Tsonga has suggested top female tennis players do not dominate because they are 'more unstable emotionally' than men.
Roger Federer's five-set victory over Tsonga on Wednesday meant the men's semi-finals of the Australian Open will involve every one of the top four seeds.
Tsonga believes it proves the world rankings do not lie and, with a cheeky smile, the 27-year-old Frenchman expressed a controversial opinion on why the top-ranked women do not dominate in a similar fashion.
"You know, the girls, they are more unstable emotionally than us," Tsonga said.
"I'm sure everybody will say it's true, even the girls."
Tsonga quickly added when female journalists disagreed: "No? You don't think?"
In a good-natured press conference, Tsonga continued his tongue-in-cheek explanation.
"It's just about hormones and all this stuff," Tsonga said.
"We don't have all these bad things, so we are physically in a good shape every time, and you are not. That's it."
While Tsonga's comments appeared to be in jest, he has opened himself up to criticism, becoming the second French tennis player to make disparaging statements about female players in a year.
Gilles Simon infamously claimed after his exit from Wimbledon last year that female players do not deserve equal prize money.
Tsonga was initially asked on Wednesday why the leading players in men's tennis, specifically Federer, Novak Djokovic, Rafael Nadal and Andy Murray, are so hard to beat and why he has struggled to beat them at grand slams.
"Maybe I'm less talented for the moment," Tsonga said after admitting he does not know what he needs to do to improve.
"In tennis, you know, you cannot lie.
"If they are number one, number two, number three, number four, it's because they deserve it and because they are the best players at the moment."