2017 US Open, Nick Kyrgios
Aug 30, 2017; New York, NY, USA; Nick Kyrgios of Australia gestures against John Millman of Australia (not pictured) on day three of the U.S. Open tennis tournament at USTA Billie Jean King National Tennis Center. USA TODAY Sports / Geoff Burke

Nick Kyrgios, the mercurial Australian tennis star, experienced yet another physical and mental meltdown Wednesday (Thursday in Australia) during his first-round defeat at the 2017 US Open. Kyrgios lost to fellow Aussie John Millman 6-3, 1-6, 6-4, 6-1 and ended hopes of a potential fourth-round tie against Roger Federer.

After hurting his right shoulder midway through the third set, Kyrgios let the frustrations get the better of him. He resorted to customary swearing and racket smashing before earning a point penalty.

In his post-match press conference Kyrgios began to wonder if he deserves to be coached by Frenchman Sebastien Grosjean. “I don’t know, honestly. I’m not good enough for him. He’s very dedicated. He’s an unbelievable coach. He probably deserves a player that is probably more dedicated to the game than I am. He deserves a better athlete than me. I’m not dedicated to the game at all," the Aussie said.

Kyrgios didn't hold back from question his own work ethic. “He’s (Grosjean) helped me a lot, especially with the training, in training sessions, but there are players out there that are more dedicated, that want to get better, that strive to get better every day, [do the] the one-percenters. I’m not that guy.”

Nick Kyrgios questions his commitment to tennis

In 2017, Kyrgios has failed to get past the second round at Grand Slams. And by his own admission, it’s been "a diabolical year." "I have had a diabolical year at these slams. It doesn’t surprise me. It’s just the story of my career, really. I will have good weeks; I’ll have bad weeks. It’s just a roller-coaster."

Entering the fourth and final Grand Slam of the year, there was more than just a glimmer of hope for Kyrgios. At the Cincinnati Masters, he stunned World No. 1 Rafael Nadal in straight sets on his way to a finals loss to Grigor Dimitrov. With top-ranked players Andy Murray, Stan Wawrinka, Milos Raonic, Novak Djokovic and Kei Nishikori pulling out with injuries, there was legitimate belief that Kyrgios would make an impact at Flushing Meadows.

“In Cincinnati, I was not doing anything different. I was probably less dedicated than I was this week. I was playing basketball at Lifetime Fitness every day for two hours. Like I played an hour of basketball before I played David Ferrer in the semi-final," the 22-year-old Nick Kyrgios, who will represent Australia at the Davis Cup later this year, added.