Column: For U.S. Open champ Marin Cilic, five-set win is no sweat even on hot, humid day

The toughest opponent for many of the tennis players at this year’s U.S. Open has been the weather. The person across the net is easy. Just please turn down that heat and humidity.

By Thursday, 12 players had dropped out of the tournament. That’s a record, and there were still 10 days to go.

They carried off Jack Sock the other day and he had so much ice packed in his clothing that his friends, now that he has recovered nicely, may take to calling him “cube.”

Mardy Fish left his grand-finale match with both legs cramping and in obvious pain, and when he met the media an hour or so later, he admitted to still not feeling well.

Heat and humidity is scary, dangerous stuff. But this is the U.S. Open. It is noisy, dusty, hyperactive New York in the throes of a heat wave. That’s the reality.

So, when Marin Cilic kind of shrugged it off Friday, looked it in the eye and said “Bring it on,” you sat up and took notice. If it is strength and endurance that will eventually win out here, then Cilic is worth paying attention to.

Of course, he is the defending champion, so he would be worth paying attention to, anyway.

His intrusion into this Grand Slam winners’ circle last year, a rarity in that he wasn’t one of the dominating big four of Novak Djokovic, Roger Federer, Andy Murray and Rafael Nadal, was taken by most as an aberration. One of those years. One of those things that’s going to happen occasionally. After all, didn’t Juan Martin del Potro win here, and how much has he done since?

Then Cilic didn’t do much after the Open, choosing to tend to an injured shoulder and not play much. He didn’t get back on the tour until March at Indian Wells, where he lost in the first round. That affirmed the aberration assumption.

Then came Friday, out on the court at Louis Armstrong Stadium, first match on in the heat of the day, and Cilic played for 4 hours 11 minutes, one of the longest outings of the tournament.

He also won, sauntered into the media center for his news conference and shrugged off weather questions like he didn’t understand what the big deal was. You get the impression that, if his car stalled in the middle of the Sahara Desert, he’d just hook his belt to the bumper and tow it the rest of the way.

“It was a bit humid, but I didn’t have any difficulties with that,” Cilic said. “I was feeling, as the match went on, that my chances were getting better and better.”

Cilic is seeded ninth. He was playing 56th-ranked Mikhail Kukushkin from Kazakhstan. And Cilic was in lots of trouble lots of the time.

Kukushkin, whom Cilic has played twice, lost to once and been in a struggle with both times, showed up as advertised, swinging all out from both sides and prepared for another war.

He won the first set in a tiebreaker, and that set took exactly an hour. Now it was high noon, both on the clock and in the style of play.

Kukushkin kept flailing, got it to a 5-2 lead in the second set, and Cilic was in trouble. Or was he?

“I’m playing a good opponent,” Cilic said, “[and] I’m going to have to stay a bit longer on the court.”

A bit longer became more than two hours.

At about this point, Kukushkin started to look like a wreck, while Cilic resembled a guy leaving his air-conditioned office to stroll for a Starbucks. Cilic made a huge rally, got it into another tiebreaker and allowed Kukushkin just one point.

It was a set apiece and Kukushkin had to be near suicidal with the opportunity he had just let slip away. And they weren’t even half done.

Cilic muscled through the third like he had this under control, winning, 6-3, and then went up a break in the fourth. But then things got, as he said, “very strange.” He had two break points for a two-service-break lead, but that slipped away, and soon it was Cilic getting bounced around in the tiebreaker, and Kukushkin had taken the fourth set.

A set that should have been completed in half an hour ended up taken 1:04.

“Things got complicated,” Cilic said.

Now the stadium was packed. Tennis fans move around and watch the monitors to see where the best drama might be. In some ways, they are ghoulish. Last year’s men’s champion had just blown a lead, was in a fifth set. They had to see this.

Whatever seats remained in Armstrong seemed to fill. But if they were looking for Cilic in full fade, or any signs of struggling, they saw little. Instead, Kukushkin sat at his chair with a large ice pack on his neck. His face was red enough to make you think that, were Rudolph not available next Christmas, Kukushkin could fill in.

This time, appearances were not deceiving. Cilic hit two aces, converted two break points, hit 11 winners and made only six unforced errors to win the final set and close out a 6-7 (5), 7-6 (1), 6-3, 6-7 (3), 6-1 victory.

Cilic probably showered afterward, but you weren’t sure he needed to.

“I was feeling,” he said, “as the match went on, that my chances were getting better and better. I was feeling that Mikhail was struggling more than me.”

There must be something remaining on the court after 4:11 in the hot sun and humidity?

“I’m not feeling physically exhausted,” Cilic said.

He was asked about his next potential opponent, No. 7 David Ferrer, a grinder from Spain, who was to play later Friday and who always seems willing to stay out there forever.

“With Ferrer,” Cilic said, “it is always a difficult battle in best-of-five-set matches.”

Then he smiled.

bill.dwyre@latimes.com

Twitter: @DwyreLATimes