Australian Open: Djokovic, Gauff labor into semis, Sinner, Sabalenka sprint

World No. 1 Novak Djokovic of Serbia and fourth seed Jannik Sinner of Italy reached the Australian Open men's singles semifinal, respectively, on Tuesday, as defending women's champion Aryna Sabalenka of Belarus set up her semifinal clash with U.S. Open's home champion Coco Gauff.

Djokovic was not at his brilliant best as he battled warm conditions in the high-voltage game against 12th seed Taylor Fritz of the U.S. But the 10-time tournament champion wore down Fritz 7-6 (3), 4-6, 6-2, 6-3 in a quarterfinal that lasted 3 hours and 45 minutes.

"He was serving well, he was staying close to the line, he was kind of suffocating me from the back of the court," said Djokovic, who now has a 9-0 head-to-head record against Fritz. "It was extremely hot while the sun was still out there. Physically very draining, emotionally as well."

Djokovic squandered his first 15 break points, but he was dominant on serve with 20 aces. "At the end of the day, I managed to break him when it mattered, in the third and the fourth," he said. "I think I upped my game probably midway through the third set, all the way to the end."

The 36-year-old remained well on track for a record-extending 25th Grand Slam title, but the irrepressible Sinner looms as a worthy challenger in the semifinals having not dropped a set in the tournament.

Sinner continued his brilliant form with a 6-4, 7-6 (5), 6-3 victory over fifth seed Andrey Rublev of Russia as he strives for a maiden Grand Slam title.

There was much anticipation over the late night blockbuster which did not start until almost 11 p.m. Sinner made a fast start until he was visibly in discomfort midway through the second set due to an abdominal injury.

The momentum appeared to be turning towards Rublev when he gained a stranglehold with a 5-1 lead in the second set tiebreak. But Sinner lifted his level and rattled off the next six points to force Rublev into climbing a mountain.

The 22-year-old showed no ill effects from his earlier injury woes to reach his first semifinal at Melbourne Park as he finished with a forehand winner to wrap up the match at 1:20 a.m. local time.

"I'm just trying to stay aggressive. It went my way, so I'm really happy," Sinner said.

Women's second seed Sabalenka raced past ninth seed and former French Open champion Barbora Krejcikova from the Czech Republic 6-2, 6-3 in just 71 minutes.

Sabalenka has not dropped a set and lost only 16 games in five matches in Melbourne for her title defense. She will be confident of exacting revenge against Gauff in a rematch of last year's U.S. Open final, where the 19-year-old home favorite won her first Grand Slam title with a comeback three-set victory.

Gauff overcame an error-strewn performance to defeat unseeded Ukrainian Marta Kostyuk 7-6 (6), 6-7 (3), 6-2 in a quarterfinal that failed to live up to great heights.

"Hopefully got the bad match out of the way and I can play even better," Gauff said. "Really proud of the fight I showed today."

Quarterfinal action continues on Wednesday when China's top-ranked player Zheng Qinwen faces unseeded Anna Kalinskaya of Russia, and men's second seed Carlos Alcaraz faces sixth seed Alexander Zverev of Germany. 

(With input from Xinhua)