Column: Defending champ Sloane Stephens falls, but Rafael Nadal prevails in five-set tiebreaker with Dominic Thiem to reach semifinal

Watching Sloane Stephens lose her chance to win a second straight U.S. Open women’s championship and, later, seeing world No. 1 Rafael Nadal scratch and claw to get past Dominic Thiem 0-6, 6-4, 7-5, 6-7 (4), 7-6 (5) to keep alive his chances of repeating as champion, had the feel of a fever dream: vivid, exaggerated, disorienting for those trapped in it and all who watched through the haze of yet another steaming hot day.

Stephens, usually so powerful and commanding, was helpless against Anastasija Sevastova’s slices and drop shots and changes of pace Tuesday at Arthur Ashe Stadium. Stephens had seven chances to break Sevastova’s serve in the first set and let them all slip away, giving her Latvian opponent life and confidence. Sevastova’s 6-2, 6-3 victory was well crafted, smart and surprising in its swiftness, although nothing that happens here should be too surprising after world No. 2 Roger Federer fell to 55th-ranked John Millman late Monday.

Stephens, the No. 3 seed, was gracious and honest about her loss to 19th-seeded Sevastova. “When you don’t play big points well, the match can get away from you,” Stephens said. “I think that’s what happened today. I didn’t convert. I didn’t play the big points well, and you don’t win matches when you don’t take your opportunities.”

True enough. Stephens earned a couple of breaks in the second set but Sevastova conquered a flurry of late jitters to capitalize on her third match point and become the first Latvian woman to reach the U.S. Open semifinals. The moment was surreal for Sevastova, who retired in 2013 after being plagued by illness and injury but returned in 2015.

She has reached the quarterfinals here each of the last two years; she was eliminated last year by Stephens.

“It was an amazing journey, this three, four years. You can’t believe,” said Sevastova, who has a quarterfinals doubles match scheduled Wednesday.

In addition to dipping into her arsenal of slices and drop shots, Sevastova played well at the net, winning 11 of 12 net points. “She plays a little different than most girls,” said Stephens, who has a sinus infection but didn’t blame that for her loss. “I thought she played solid today. The better player won.”

Nadal, the indefatigable 17-time Grand Slam winner and current French Open champion, experienced the indignity of an opening-set bagel while Thiem, the No. 9 seed, ripped winners past him with startling ease.

Slowly and purposefully, with the same attention to detail he exhibits when he lines up his water and energy drink bottles just so at courtside, Nadal pushed back and back against his Austrian opponent until he was in front.

Nadal, who will face No. 3 Juan Martin del Potro in a semifinal Friday, pulled even against Thiem by winning a 44-minute second set and surged ahead in a 66-minute third set, rebounding after Thiem had broken Nadal’s serve for a 4-3 lead. Nadal, a three-time champion in New York and a crowd favorite around the world, broke for 5-5, held for 6-5 and broke to win the third set, firing up a crowd that has long loved the emotive Spaniard.

Thiem missed a break point while up 3-1 in the fourth set, and his unforced errors began to pile up. Nadal broke for 4-4 in the fourth set on a long backhand that Thiem unsuccessfully challenged, saved a break point in the next game and held for a 5-4 lead when Thiem sent a backhand long. But Thiem wasn’t finished, winning at love to bring them even at 5-5.

He had a break point in the next game, but Nadal prevailed on a drop shot and a return that was netted by Thiem. But Thiem held for 6-6 though, sending them to the tiebreak; Thiem won the 81-minute set when Nadal netted a forehand as he approached the net.

The fifth set started at 12:55 a.m. EDT, no doubt leaving many spectators glad that the New York City subways run 24 hours a day. The quality of play remained good and Nadal and Thiem stayed on serve through the first 10 games of the fifth set, though Thiem had to save two break points in the fifth game and three more in the 11th game to keep it that way. Finally, after Nadal held serve to make it 6-6, they went to the tiebreaker. The drama continued until 2:03 a.m. Eastern time, when Thiem hit an overhead long and Nadal advanced to the U.S. Open semifinals for the seventh time of his career.

“A great battle,” Nadal said. “The conditions were tough.”

But he was tougher and his title hopes are still alive.

helene.elliott@latimes.com

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