Nick Kyrgios Is Having a Very Good U.S. Open. Make That Summer.

His tennis, always sublime some of the time, has been sublime far more of the time.

There is no arguing with Nick Kyrgios’s recent results: a first-time Grand Slam singles final at Wimbledon in July; a singles title in Washington, D.C., in August; and now a best-ever run to the quarterfinals of the U.S. Open in September after outclassing the defending champion Daniil Medvedev, starting and finishing with an ace down the T and knocking the Russian from the No. 1 spot.

“I was just really sick of letting people down,” he said after his victory, 7-6 (11), 3-6, 6-3, 6-2, over Medvedev on Sunday night. “I feel like I’m making people proud now. I feel there’s not as much negative things being said about me. I just wanted to turn the narrative around almost. That’s basically it. I just was feeling so depressed all the time, so feeling sorry for myself. I just wanted to change that.”

It is good to see a gifted tennis player making fuller use of his gifts. Good to hear an oft-tormented man sound like he has found, for now, a measure of peace, though Kyrgios is still no Zen master; still no angel.

Off court, he faces charges of assault from a former girlfriend and a court hearing in Australia scheduled for next month, as well as a defamation suit in England, brought by a British fan that Kyrgios claimed “was drunk out of her mind” during one of his Wimbledon matches.

On court, he is still a magnet for fines (and fans) at age 27 and a combustible, foul-mouthed racket smasher with a nasty spitting habit, all of which makes the Kyrgios show less than ideal family entertainment.

He tossed a few more rackets on Sunday night as he beat Medvedev for the fourth time in their five matches and for the first time in a major tournament. He also, as so often, directed a few more oaths at his support team even as they gave him nothing but encouragement.

“Stay focused Nick!”

“No negative energy, man!”

“You can do it!”

Yes, he could. His victory over Medvedev was an often-dazzling mix of power and finesse.

Thunderous serves followed by feathery drop shots that an out-of-sorts Medvedev was unable to reach or control despite his foot speed and big wingspan at 6-foot-6.

Deft backhand chips that just barely cleared the net followed by fully ripped forehand winners on the move.

Patient backcourt exchanges followed by serve-and-volley to keep Medvedev from camping out behind the baseline to return.

Krygios has all the shots and though he is still without a formal coach, he said he has tried to address his weaknesses this year by improving his fitness, his second-serve variety and above all his forehand return.

What makes him so tough to neutralize on a night like Sunday are the abrupt shifts in rhythm and tactics. It is hard, even for a supreme defender and pace absorber like Medvedev, to settle in for long. It is the upside of Kyrgios’s short attention span: a resistance to routine.

What also made Kyrgios tough to beat was his refusal to implode even if he seemed to be reaching a boil in the opening set, the pièce de résistance of this particular tennis spectacle.

The latest sellout crowd of nearly 24,000 could sense the danger, too, and though there were a few Medvedev fans in attendance, it was much easier to hear the Kyrgios supporters, who know their man at this stage.

“Come on Nick!”

“Keep it together!”

“Don’t get distracted!”

With coaching from the stands allowed on a trial basis at this year’s U.S. Open, Kyrgios had no shortage of volunteer coaches, and it seemed they sensed the precarity of this state of tennis grace.

Medvedev had three set points in the tiebreaker. Kyrgios saved them all and then failed to convert three set points of his own.

After faltering on the second point, he screamed at his team, using an expletive: “Tell me where to serve!” After the third, he wheeled and spiked his racket. But on the next point, he hit a perfectly weighted drop shot winner, and then secured the set when Medvedev missed a forehand wide with a passing lane available.

In the third set, with Medvedev serving in the second game at 30-all, Kyrgios fired a forehand passing shot that Medvedev could only deflect with his racket, sending the ball high in the air on his own side of the net. Kyrgios watched its flight and then, presumably sensing a chance to entertain, ran past the net post and, before the ball landed, knocked it past Medvedev into the open court, wagging his index finger triumphantly.

There was only one problem: It is against the rules to strike a ball in the air on your opponent’s side of the net unless it has first bounced on your side and then spun back. Instead of break point for Kyrgios, it was 40-30 for Medvedev, who went on to hold serve.

It was a bonehead move, as Kyrgios would concede later, but again, no Kyrgios implosion — only banter with his box. “I thought it was legal when I did it,” he said, while sweeping the next three games to take command of the match for good.

As a result, men’s tennis is guaranteed to have a new No. 1 after the U.S. Open.

“Not going to cry in the room, but I’m a little bit disappointed,” Medvedev said.

It has been a strange and unsettled season for the Russian star. He blew a two-set lead in the Australian Open final and lost to Rafael Nadal, was banned from Wimbledon because of Russia’s invasion of Ukraine and then ran into Kyrgios in New York on a night when Medvedev said he was feeling slightly ill and low on energy down the stretch.

But he conceded that he had been feeling fine when Kyrgios beat him last month in the second round of the National Bank Open in Montreal.

The new No. 1 after the U.S. Open could be Nadal, who has been there before but never at age 36. It could also be 19-year-old Carlos Alcaraz or 23-year-old Casper Ruud.

Nadal and Marin Cilic, who faces Alcaraz in the fourth round on Monday night, are the only men left in the draw who have won the U.S. Open or, for that matter, any major singles title.

Medvedev thinks Kyrgios has a shot to join them, and it is tempting to agree.

“He’s tough to play,” Medvedev said. “He has an amazing serve, but from the baseline it’s not like when the point starts, you know you have the advantage.”

Medvedev continued: “If he plays like this ’till the end of the tournament, he has all the chances to win it, but he’s going to get tough opponents.”

Next up in Kyrgios’s first U.S. Open quarterfinal is another Russian, Karen Khachanov. Win Tuesday and Kyrgios would face either Matteo Berrettini or Ruud in the semifinals.

Despite Kyrgios’s often-glittering record against highly ranked players, he is 1-1 against Khachanov and Ruud and 0-1 against Berrettini.

But Kyrgios, never at his best in New York until now, looked inspired for much of Sunday night with the big crowd mostly in his corner and showing love for his flashy shotmaking.

“I hadn’t won a match on Ashe before this week, and now I’ve won two against two quality opponents,” he said. “I feel like I’ve been able to showcase. There’s a lot of celebrities here, a lot of important people here watching. I wanted to get on that court and show them I am able to put my head down and play and win these big matches.”

Stay inspired, whatever the reasons, and he just might pull this off. He certainly is looking for a reward before he heads back to Australia after being on the road for several months with his girlfriend Costeen Hatzi.

“We’ve got to try and just tough it out and keep pushing each other, keep being positive,” he said. “We do realize it’s next week we’re going home, but three more matches potentially, then we never have to play tennis again.”

A throwaway line or a promise? Kyrgios, like his serve, is not always easy to read.