Portugal Colonial - Gauff keeps US Open repeat bid alive, Tiafoe outlasts Shelton

The 20-year-old American opened the action on Arthur Ashe Stadium, where men's defending champion Novak Djokovic aimed to further his bid for a record 25th Grand Slam title against Alexei Popyrin.

Gauff's third-set surge had carried her to triple match point at 5-2, but she delivered a pair of double faults and Svitolina saved another with a blazing backhand on the way to a break.

But Gauff broke Svitolina at love in the next game to lock up the win in a tense physical encounter that featured one 37-shot rally.

Gauff regrouped after a rocky end to the first set saw Svitolina break at love for a 5-3 lead and pocket the opener with a love game.

"I lost, like eight points in a row at the end of the first set, probably more," Gauff said. "I knew I needed a reset at that point."

Gauff gained her first break of the match on her fourth opportunity for a 4-2 lead in the second and held on to force the third. She won nine games in an 11-game span.

"I knew today was going to be a tough match -- she's a fighter," Gauff said, saying more aggression on her forehand and fewer backhand errors helped her turn things around.

She lined up a last-16 clash with fellow American Emma Navarro, who upset Gauff in the fourth round at Wimbledon. Navarro beat Ukraine's Marta Kostyuk 6-4, 4-6, 6-3.

Gauff had fans in Arthur Ashe on the edge of their seats, but Frances Tiafoe and Ben Shelton brought them to their feet in a five-set, four-hour thriller that Tiafoe won 4-6, 7-5, 6-7 (5/7), 6-4, 6-3.

It was a dogfight between the young American rivals. Shelton gained the upper hand with a dramatic third-set tiebreak victory, taking a 6-0 lead only for Tiafoe to win five straight points before Shelton closed out the set with a 143 mph ace.

"Highlight after highlight," said Tiafoe, who grabbed the only breaks in each of the last two sets. "I really hope you guys enjoyed the show."

Tiafoe next faces either Djokovic or 28th seeded Australian Popyrin.

Djokovic has won all three of their prior meetings, including at the Australian Open and Wimbledon this year, but the Serbian superstar had reason to be wary with Popyrin riding the high of the biggest title of his career at the Montreal Masters this month.

Djokovic won the Olympic singles gold he coveted at the Paris Games, but that was a rare high spot in an uneven season and last year's US Open title, which saw him tie Margaret Court for most all-time Grand Slams with 24, is his most recent major triumph.

Second-seeded Australian Open champion Aryna Sabalenka closed out the night session, taking on Russian Ekaterina Alexandrova.

The two have split their six prior meetings, Sabalenka winning most recently in the fourth round at Wimbledon last year.

- Zheng cruises -

Seventh-seeded Olympic gold medallist Zheng Qinwen of China, who rallied from a set down in each of her first two matches, dispatched Germany's Jule Niemeier 6-2, 6-1.

"Finally, it's the first match I won in two sets," said Zheng, who next faces Croatian Donna Vekic in a rematch of the Paris Games gold medal match.

Vekic beat American Peyton Stearns 7-5, 6-4.

Spain's Paula Badosa saved a match point en route to a 4-6, 6-1, 7-6 (10/8) victory over Romanian qualifier Elena-Gabriela Ruse, who had toppled Wimbledon champion Barbora Krejcikova in the second round.

In men's action, fourth-seeded Alexander Zverev took on Tomas Martin Etcheverry in a rematch of their 2023 Roland Garros quarter-final.

World number six Andrey Rublev of Russia beat Czech Jiri Lehecka 6-3, 7-5, 6-4 to line up a meeting with Grigor Dimitrov, a 6-3, 6-3, 6-1 winner over Tallon Griekspoor.

A.Motta--PC