Roger Federer has a typically Swiss take on the debate over Serena Williams' actions and the penalties handed down by the umpire in her US Open defeat.

The 20-time grand slam champion has spoken publicly for the first time following Williams' meltdown in her US Open final defeat to Japan's Naomi Osaka.

Federer has made some very neutral comments about whether umpire Carlos Ramos overstepped the mark in his handling of the situation and if there is a gender bias in tennis.

"It's interesting but I think it's important to look at it," Federer told Texas TV station KVUE while attending a charity event for former rival Andy Roddick.

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"Every umpire has their own style, it's just how it is in any sport.

"In tennis you might have an umpire that gives more coaching violations and another guy goes more to time violation.

"You might get one guy who knows that this guy misbehaves quite often so I'll give him a warning quicker or I'll be more lenient with a guy because he's a nice guy and just can't control himself. I think it really depends on the situation.

Federer said the debate has been "tricky but a really interesting case to study".

"I hope it's not the case (that there is gender bias) but I think what happened, obviously there was mistakes along the way and there should be more discretion sometimes.

"At the same time, they have to do their job, that's what we want them to do."

Earlier this week Williams broke her silence for the first time on the outburst that turned the women's final into an international controversy.

The 36-year-old blew up after she was penalised for being coached from the sideline and racket abuse.

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Despite coach Patrick Mouratoglou admitting he was coaching from the box, Williams doubled down on her claim, insisting she knew nothing about it.

"He said he made a motion," she told The Project, in an interview to air next week. "I don't understand what he was talking about. We've never had signals."

Williams also reiterated her claim that female stars were treated differently to the men on tour.

"I just don't understand … if you're a female, you should be able to do even half of what a guy can do," she continued.