Australian teen Thanasi Kokkinakis, foiled by cramps while poised for the biggest victory of his young career, left the US Open frustrated after his body quit before he did.

Kokkinakis, best known for being named by compatriot Nick Kyrgios in the infamous sex slur he uttered in a match against Stan Wawrinka in Montreal last month, reminded people why he is considered a top young tennis star with his valiant performance.

The 19-year-old from Adelaide broke French 12th seed Richard Gasquet in the last games of the first and third sets and was off to a solid start in the fourth when the cramping began.

Kokkinakis fought on for a set, ignoring the umpire's advice that he was putting his health at risk, before finally handing Gasquet a first-round victory by retirement at 4-6, 6-1, 4-6, 6-3, 2-0 after two hours and 51 minutes and calling it the most devastating loss he has yet suffered.

"It's just frustrating 'cause I started playing good tennis. I was getting fired up," Kokkinakis said. "One-All, 30-love in the fourth set, I was bouncing the ball. Then, immediately I started to feel my forearm go. I'm like, 'Oh no, this is bad.'

"I didn't feel tired physically either, which is the most frustrating thing about it. I actually felt all right. My energy levels were good and then I went up to hit a swing and volley or something and both my calves -- it was just disaster.

"I'm pretty shattered."

Kokkinakis sacrificed the fourth set to buy time, receiving treatment and hydrating in a desperate effort to combat the cramps that had him struggling to move around Court Five.

He served underhand on the last point of the fourth set, his 131-mph serve reduced to 75 mph or less.

He couldn't chase after balls on points, leaned on his racket for support to stay standing at times and after he finally retired, slammed down his racket in frustration before walking to the net to shake hands with Gasquet, he apologized to the spectators who stood and applauded his gallant effort.

"I wanted to keep going because I had it happen when I was 17. The other guy was struggling then, too. I was able to find a way there. It was actually OK," Kokkinakis said.

"But once it went here, I started to feel it everywhere, different spots on different shots. I was like, this is tortuous for everyone watching as well. It was frustrating. I didn't want to do it.

Kokkinakis found himself cramping in the shower despite drinking "a ridiculous amount of liquids".

"Would have been one of the biggest wins of my career. Maybe the emotions. I don't know if I got too fired up. I was trying to push through. I hit the odd winner, but I couldn't sustain that. And with a player like him, if you're not 100 percent, he's going to move you around. I was dust."

- Kyrgios comments 'sorted' -

Kokkinakis said he and countryman Kyrgios have put the controversial comments of Montreal behind them.

"I'm past it. We talked. It's sorted. It's not really an issue for me anyway at the moment," Kokkinakis said.

"I've known him for ages. One little thing isn't going to change too much. That's not ideal what happened, but I've talked to him. I've talked to everyone in the incident. I've moved past it and I'm sure they will, too.

"He was obviously frustrated. He felt Stan was giving him something. I was watching the match. I didn't really see too much. Then my Twitter blew up. He said it. Yeah, he plays on a lot of emotions. I don't think he meant to get at his opponent. But, yeah, he said some stuff. I'm sure he regrets what he said. But it's out of my control."

Kokkinakis will next prepare for Australia's Davis Cup semi-final tie against Andy Murray-led Great Britain at Glasgow on September 18-20.

"No disrespect to Scotland. I don't think I'll be getting there too early," he said.

Source: AFP