Nick Kyrgios of Australia reacts to defeating Daniil Medvedev on day seven of the 2022 U.S. Open tennis tournament at USTA Billie Jean King Tennis Center. Danielle Parhizkaran-USA TODAY Sports

Nick Kyrgios is enjoying his best run ever at the US Open, which is also coming during the best stretch of his career. The talented 27-year-old says that his girlfriend, Costeen Hatzi, is a big reason for his recent success.

Kyrgios on Sunday night eliminated top seed Daniil Medvedev from the US Open with a 7-6(11), 3-6, 6-3, 6-2 win in the fourth round.

Kyrgios, who previously had never advanced past the third round at the US Open, is now on to the quarterfinals.

The Australian was interviewed by Patrick McEnroe after his big win over Medvedev and was asked when things started to click for him. The notorious headcase credited his girlfriend for helping him maintain his focus in New York for the first time in his career.

“I’m just trying to make every practice session count. Getting to sleep — I would probably be out every night before. Now, I’ve got a great girlfriend … she helps me … and my team,” Kyrgios said, crediting his support staff. “I’ve got my physio with me. It’s all my team. I’m just really happy and hopefully I can keep it going. I’m just working really hard.”

One of the biggest complaints fans had about Kyrgios — aside from his conduct on the court — was his immaturity. Fans always knew he had the talent to succeed, but it was upsetting seeing him underachieve because of a lack of focus and dedication.

Now Kyrgios has finally started to dedicate himself, and he is reaping big rewards.

Kyrgios even said in his interview that he was happy to finally show fans the work and dedication he has put in.

“Glad to show them the work and dedication finally … took 27 years,” Kyrgios admitted.

Kyrgios’ quarterfinals appearance at Flushing Meadows comes after his run to the finals at Wimbledon in July. He will face Karen Khachanov in the quarters.

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