NEW YORK (AFP) — Defending champion Carlos Alcaraz fended off hard-hitting Wu Yibing in straight sets on Friday and says his game is “getting there” as he hits the US Open fourth round.

Alcaraz, coming off a four-month injury absence, beat Wu 6-3, 6-4, 6-1 and joined women’s two-time defending champion Aryna Sabalenka in reaching the Round of 16.

China’s Wu, a former US Open boys’ champion whose pro trajectory has been disrupted by multiple injuries, pressured Alcaraz with his aggressive baseline game.

But despite moments of frustration Alcaraz rose to the challenge and will face 20th-seeded American Tommy Paul for a place in the quarter-finals after Paul beat 15th-seeded Alexander Bublik 6-4, 3-6, 6-7 (4/7), 6-1, 6-3.

“The way he plays is unbelievable, the rhythm he has on every shot — forehand, backhand,” Alcaraz said of Wu. “His balls skid a lot on the court and, for me, it’s really difficult to control sometimes.”

“But I think I stayed there. I played aggressively. I played smart in the toughest moments.”

Wu recovered an early break in each of the first two sets, but Alcaraz pocketed both with breaks in the final games and after saving a pair of break points in the first game of the third the Spaniard rolled home.

“I think my level is really good,” he said. “I’ve got into the rhythm of the competition. I’m getting there.”

World No. 1 Sabalenka didn’t face a break point in her 6-3, 6-4 victory over Kamilla Rakhimova, firing 29 winners with 10 aces.

The numbers didn’t tell the whole tale of a match that saw 92nd-ranked Rakhimova challenge Sabalenka in a second-set slugfest.

“She played incredible tennis, she really pushed me so hard in the second set,” Sabalenka said. “I’m super happy that I was able to close this match in straight sets because she’s a fighter.”

Sabalenka, whose world No. 1 ranking is under threat in New York, got off to a strong start, breaking Rakhimova in her first service game and holding her own serve with ease.

Sabalenka didn’t miss a first serve until the seventh game of the contest, taking the first set in 35 minutes.

But Uzbekistan’s Rakhimova dialed up the power in the second set, which featured mammoth service holds from each player before Sabalenka gained the crucial break for a 5-4 lead.

Sabalenka, who must repeat as champion to have a chance of remaining number one, next faces Taylor Townsend, the 96th-ranked American who beat 15th-seeded Russian Diana Shnaider 6-2, 6-7 (3/7), 6-3.

Third-seeded American Jessica Pegula, one of the players with a chance to knock Sabalenka off her No. 1 perch, mounted a desperate fightback to beat Canadian Leylah Fernandez 1-6, 6-4, 6-3 in a battle of former finalists.

Pegula struggled early with the varied spin and speeds of the Canadian lefty’s serve.

“I never feel comfortable playing her,” Pegula said. “I’m really glad I was able to find something there, especially in the second set to turn things around.”

In other early matches, Ukraine’s Marta Kostyuk beat Russian Ekaterina Alexandrova 6-3, 6-2 and American Emma Navarro upset seventh-seeded Czech Karolina Muchova 6-3, 7-5.

The night session features the return to Ashe of a US tennis great as 23-time Grand Slam singles champion Serena Williams teams up with sister Venus in doubles, taking on the 14th-seeded duo of Chan Hao-ching and Maya Joint.

Venus and Serena won two of their 14 Grand Slam doubles titles together at the US Open, where they first competed in 1997.

Their first doubles appearance together in a major since the 2022 US Open comes after 23-time Grand Slam singles champion Serena returned from almost four years away from professional tennis to play at Wimbledon.

A knee injury in her first-round defeat — to Australia’s Joint — scuppered plans for the sisters to play doubles at Wimbledon.