Canada's Gabriel Diallo advances via walkover over Belgian David Goffin at Shanghai Masters

Gabriel Diallo of Montreal advanced to the men's singles Round of 16 at the Rolex Shanghai Masters tennis tournament with a 12-minute victory on Saturday night.

The 31st-seeded Diallo was a dozen minutes into his Round of 32 match against David Goffin, and ahead 3-0, when the Belgium player retired citing injury.

Diallo will face Belgium's Zizou Bergs on Tuesday. Bergs upset 19th-seeded Francisco Cerundolo 7-6 (1), 6-3.

In other Round of 32 matches, Denis Shapovalov of Richmond Hill, Ont., is scheduled to play Jiri Lehecka of the Czech Republic, while Felix Auger-Aliassime of Montreal is scheduled to play Jesper de Jong of Netherlands.

Novak Djokovic was made to work hard before he rallied past German qualifier Yannick Hanfmann 4-6, 7-5, 6-3 on Sunday morning, while defending champion Jannik Sinner retired due to severe leg cramps.

After taking the opening set, Sinner, who won the China Open in Beijing, trailed 7-6 (3), 5-7, 2-3 against Tallon Griekspoor when he abandoned the match in humid conditions.

Sinner massaged his right thigh during the decider.

"This is definitely not the way you want to win," Griekspoor said. "Brutal conditions here in Shanghai all week already. I thought we were a little bit lucky to play in the evening without sun, but two hours and 36 minutes on the clock, middle of the third set... I'm sorry for him, I wish him a speedy recovery."

Djokovic struggled to cope with Hanfmann's big serve and excellent play at the net. He needed two hours and 45 minutes to progress. He'll be up against Jaume Munar in the next round. Djokovic was sick during the second set and threw up during a changeover.

"It's the same for every player out on the court, but it's brutal," Djokovic said of the conditions. "It's brutal when you have over 80 per cent of humidity day after day, particularly for the guys when they're playing during the day with heat, with sun, it's even more brutal."

Djokovic is bidding for a record-extending fifth title at the Shanghai Masters.

Big-serving Frenchman Giovanni Mpetshi Perricard upset fourth-ranked Taylor Fritz 6-4, 7-5 and advanced to the fourth round.

Mpetshi Perricard sent down 12 aces, to Fritz's nine, and took a break in each set as he clinched his first tour victory against the American in one hour and 25 minutes to set up a last-16 meeting with 10th-seeded Holger Rune.

Rune beat 21st-seeded Ugo Humbert 6-4, 6-4.

Top-ranked Carlos Alcaraz, who won the Japan Open last week, is not in Shanghai due to minor ailments.