Daniil Medvedev, Novak Djokovic and Rafa Nadal warned of Nick Kyrgios threat at US Open

US Open favourites Daniil Medvedev, Novak Djokovic and Rafa Nadal have all been warned about in-form Nick Kyrgios ahead of the tournament. Kyrgios is enjoying some of the best form of his career and recently won both singles and doubles titles at the Citi Open.

Kyrgios defeated Noshihito Nishioka in Sunday's singles final, and teamed up with Jack Sock to win in the doubles draw. It came after the Australian reached the final of Wimbledon, albeit benefitting from Nadal's withdrawal ahead of their semi-final before losing to Djokovic at the last hurdle.

But former World No 1 Kim Clijsters believes the best players in the world should be fearful of Kyrgios due to his form during the hardcourt season. The four-times Grand Slam champion says she cannot wait to see the 27-year-old at the US Open, which starts later this month.

Clijsters tweeted: "There is something about @NickKyrgios, his energy on these American hardcourts! Can't wait to see him compete at the US Open."

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Kyrgios believes he has been one of the best players in the world this season and has put his hard work down to a successful training block ahead of the Australian Open in January. He was excellent at Wimbledon but came unstuck against the exceptional Djokovic.

"I think it's a reflection of the last six months of how hard I have been working. I'm just really happy to continue the form after Wimbledon," Kyrgios, who has previously struggled for consistency and motivation, said after the Citi Open.

"I think you have got a small window after a Grand Slam that people kind of fear you before they step out on the court. I feel like I made the most of it this week. I'm really happy