epa05112410 Roger Federer of Switzerland plays a shot to Alexandr Dolgopolov of Ukraine during their second round match at the Australian Open tennis tournament, in Melbourne, Australia, 20 January 2016.

Dimitrov opened strongly against his opponent, ranked 210th in the world, whose win in the first round was his first at a Grand Slam, taking an early lead and winning the first set in half an hour.

The Japanese player was broken serving for the second set when he double-faulted and he was far from convincing in the tiebreaker, before finally sealing it when the American's forehand went wide.

No. 1-ranked Novak Djokovic was put on the spot Wednesday at a post-match news conference, where a reporter told him an Italian newspaper had just reported that he "wanted to lose" a match in Paris in 2007.

Given that the majority of Federer's aces were hit out wide, Dimitrov will do well to cover that area of the court in a bid to nullify one of the most effective serves in the men's game.

The image of the twins seemingly uninterested in the ongoing match was shared on Twitter and, as expected, went viral with several users poking fun at Federer.

"It's like I can always train more - there's always more you can do", The Telegraph quotes Federer as saying. I have gone through spells of these and they are the worst.

And then in his courtside interview, Federer said his six-year-old girls Charlene Riva and Myla Rose were not looking like they would become future professionals.

Roger Federer regards the spectre of match-fixing as serious but the Swiss superstar is unhappy with speculation regarding the issue in tennis.

But as third seed, Federer could scarcely have drawn a tougher round-three opponent than Grigor Dimitrov.

"I'm very happy", said the four-time Australian Open champion.

But as Federer enters his 35th year, the Swiss is still competing for grand slam titles while Dimitrov has yet to fulfil the potential he first showed the world when he won the junior Wimbledon title in 2008. "I think I got at least 8-9". "You know, it's a good start", Dimitrov said.

His 6-3, 4-6, 6-2, 7-5 win over Argentina's Marco Trungelliti was not as fluent as he would like but the Bulgarian is carrying some confidence.

Despite Federer's ideal record against Dimitrov he said he respects how risky Dimitrov's game is in an interview. One of former U.S. Open champion Marin Cilic, Spaniard Roberto Bautista Agut, young Australian Nick Kyrgios or sixth seed Tomas Berdych will make it through to the last eight in that section.

"To come back here and play my first match on Rod Laver is always very special as you always get those first little jitters out of the way". I don't really understand how it all works.