US Open 2018: Nick Kyrgios aims for Roger Federer upset

Nick Kyrgios says he relishes being the underdog in Saturday's US Open third-round match against five-time champion Roger Federer.

The Australian, then 20, beat Federer at the 2015 Madrid Open when the pair met for the first time.

He similarly beat Rafael Nadal and Novak Djokovic, who have a combined total of 30 Grand Slam titles, at the first time of asking.

"It's better to be the underdog than have all the pressure," he said.

"I'm going to put a lot of expectation on myself to play well. I'm not going to go out there and roll over and be happy to be out there. I do believe I can win."

While Kyrgios revels in high-profile contests, his motivation has been lacking on other occasions.

His second-round win over France's Pierre-Hugues Herbert came after umpire Mohamed Layhani encouraged him to play better, apparently concerned that the world number 30 was not trying his best in the match.

Kyrgios was fined for unsportsmanlike conduct after quitting his first-round match against American Steve Johnson in Shanghai in October, a year after he was similarly penalized for failing to compete properly against Mischa Zverev at the same tournament.

After that match in Shanghai Kyrgios was publicly criticized for his behavior by legendary coaches Nick Bollettieri and Reno Manne.

Manne called for Kyrgious to be given a match ban by the ITF whilst Bollettieri called the young Australian a bad role model for the game.

He clashed with the umpire in his 2015 Wimbledon defeat by Richard Gasquet after apparently writing off the second set.

Federer, who won the pair's other two matches on final-set tie-breaks, told ESPN that Kyrgios, who does not have a coach, needs more consistency to realise his potential.

"I think he finds it hard to not do any of those tricks," the Swiss said.

"I'm not sure if I'm the guy who's supposed to pull him to the side. I think he very well knows, deep inside of himself, what he also needs to do."

Elsewhere on Saturday, 21-year-old Latvian Jelena Ostapenko, who won the French Open in 2017, takes on five-time Grand Slam champion Maria Sharapova.

Wimbledon champion Novak Djokovic plays French 26th seed Richard Gasquet in the final match on the centrepiece Arthur Ashe Stadium.

Defending champion Rafael Nadal dug deep to outmanoeuvre powerful Russian Karen Khachanov