'Not fair': Roger Federer's startling admission about Australian Open victory

Roger Federer has admitted he felt sorry for his opponent after steamrolling Filip Krajinovic at the Australian Open on Wednesday.

An ageless Federer left Krajinovic's head spinning as he raced into the third round with a straight-sets victory on Rod Laver Arena.

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It was all too much for Krajinovic, who had to play twice in 24 hours (including a five-setter on Wednesday) following the deluge of rain that hit Melbourne Park on Monday.

When asked by John McEnroe whether he felt sorry for his opponent, Federer admitted: “A little bit, actually.

“At 0-40 and 5-1, it wasn’t 100% fair that he played five sets yesterday and me zero.

“The rain helped me, so you’ve got to take them when they fall that way.

“But, yeah, I do feel a little bit sorry like this, to be honest. You have to take advantage of it, I don’t know.”

Federer sets up Millman rematch

Federer needed just 20 minutes to wrap up the first set against the Serbian world No.41 before going on to seal the match in a masterclass performance 6-1 6-4 6-1.

The Swiss maestro next takes on Australian John Millman, who also had a straight sets second round win over Poland's Hubert Hurkacz.

The Australian famously ousted the 20-time major champion in the the round of 16 at the 2018 US Open.

The win was Federer's 99th at the Australian Open and 21st straight third-round appearance but it was the manner of it that left commentators searching for superlatives.

McEnroe described Federer as "absolutely phenomenal", with the 38-year-old blasting 42 winners, 14 aces while not making a single double fault.

Krajinovic wasn't even playing that badly with his first serve percentage in the first two sets at 90 per cent.

Federer admitted he even felt a little sorry for his opponent, who had to battle through a five-set first round match lasting almost four hours on day two.

"At 0-40 and 5-1, it wasn't 100 per cent fair that he played five sets yesterday and me zero," Federer said.

"The rain helped me, so you've got to take them when they fall that way but I do feel a little bit sorry to be honest."

There were questions over Federer's match fitness after he skipped the ATP Cup to instead train at home in Switzerland but the world No.3 said he was feeling sharp.

"It's a great start to the season so far and I'm feeling really relaxed out on court," he said.

"You train hard and hope it pays off and not that it was all for nothing.

"I'm happy, I'm still going and looking forward to the next one, of course, and hopefully another good match."

with AAP