NEW YORK

Nick Kyrgios does what he wants and says what he wants on a tennis court, seemingly no matter the ramifications, and amid all the near-napping, cursing and racket smashing, he troubled Andy Murray for moments at the U.S. Open.

Only for brief moments, though.

In the tournament’s mostanticipated first-round matchup, the No. 3-seeded Murray hit 18 aces, saved 11 of 14 break points and, perhaps most importantly, stayed steady in the face of Kyrgios’ various distractions, putting together a 7-5, 6-3, 4-6, 6-1 victory Tuesday night.

“Obviously, for me, it’s important when you’re playing against him,” Murray said, “to just concentrate on your side of the court.”

This was Kyrgios’ first match since he was essentially put on probation by the ATP, with the threat of a 28-day suspension and $25,000 fine if he misbehaves at one of the tour’s sanctioned events over the next six months. Those parameters don’t apply at the U.S. Open, however, because Grand Slam tournaments are sanctioned by the International Tennis Federation.

That stemmed from some trash-talking last month against Stan Wawrinka in Montreal, where a courtside microphone picked up Kyrgios saying that his pal, Australian pro Thanasi Kokkinakis, had been with Wawrinka’s girlfriend. Kyrgios was fined a total of $12,500 the next day by the ATP, which later said it would monitor his behavior.

“I thought I’ve been dealing with that pretty well. Obviously it’s been tough. But I think I’ve moved on from it,” the 20-year-old Kyrgios said at Tuesday’s postmatch news conference, referring to the whole Montreal episode and its aftermath. “I’d like to think that I’m going to learn from it. I think I have. I think I’m on the right path. I don’t think any of us in this room right now were perfect at 20. Speak up if you were.”

When that was greeted by silence from reporters, Kyrgios nodded and said: “Thought so.”

Later, asked what he meant by saying he had learned something along the way, Kyrgios replied: “Keep your mouth shut at times.”

Against Murray, Kyrgios was not exactly concerned with containing himself.

He was given a warning by chair umpire Carlos Ramos for swearing too loudly. He complained to Ramos that spectators were being allowed to wander to their seats during a game. He spiked his racket against the court and later whacked it against a wall behind the baseline. He won a point with the help of a shot between his legs. He whiffed on a leaping overhead attempt. Most oddly, Kyrgios leaned all the way back in his changeover chair during breaks, closing his eyes and resting against his towel or clutching it like a kid’s blanket, looking as if he were about to doze off.

“ Just taking a nap, I guess,” he said afterward. “It’s good for you.”

Boris Becker, a six-time major champion as a player and now No. 1 Novak Djokovic’s coach, sat courtside for the match. In an on- air interview during ESPN’s broadcast, Becker said Kyrgios could stand to talk a little less and “should be famous for his on-court performance and not his antics.”

What happened in Montreal has been a chief topic of conversation in tennis over the past few weeks, and Murray was asked to weigh in before facing Kyrgios, who is ranked 37th and is talented enough to have stunned Rafael Nadal at Wimbledon last year and beaten Roger Federer this year.

“We all make mistakes … and for him, it’s unfortunate that’s its happening in front of millions of millions of people,” said Murray, the 2012 U. S. Open champion. “And I think it’s wrong, a lot of the things that he’s done, but I also think that he’s still young, and everyone’s different. People mature and grow up at different rates.”

Asked Tuesday about the tour’s handling of the matter, Wawrinka, a twotime major champion who could face Murray in the U. S. Open quarterfinals, said: “ I don’t care much about that anymore.”

Kokkinakis, similarly, told reporters: “ I’ve moved past it. I’m sure you guys will at some point, too.”

Kokkinakis stopped playing Tuesday because of cramps against 12thseeded Richard Gasquet, one of a record 12 midmatch retirements in the first round at Flushing Meadows, where the temperature has topped 90 degrees and the humidity has been heavy.

The previous mark for most players quitting because of injury or illness during any round of any Grand Slam tournament in the professional era, which dates to 1968, was nine in the first round of the 2011 U. S. Open.

Ten men and two women have dropped out so far, including five Tuesday: Kokkinakis, Marcos Baghdatis, Ernests Gulbis, Aleksandr Nedovyesov and Marina Erakovic.

“ For sure,” Wawrinka said, “ it’s surprising to see so many players pull out.”