SHANGHAI - Defending champion Jannik Sinner retired on Sunday from the Shanghai Masters after suffering from cramps in his third-round match against the Netherlands' Tallon Griekspoor, easing the way for Novak Djokovic's shot at a record-extending fifth title.
The 38-year-old Serb battled through to the last 16 with a 4-6, 7-5, 6-3 win over qualifier Yannick Hanfmann, despite admitting that he had been "hanging by a rope" early in the match.
It was a sorry end for Sinner, who had been hoping this week to add to his China Open victory.
The world number two began to experience issues in the fourth game of the third set, trying doggedly to persevere before abandoning the match at 6-7 (3/7), 7-5, 3-2.
Sinner ended the fourth game crouched over in pain and limping around the court.
He tried to play through it but did not improve, hitting the ball into the net multiple times to provide an easy break for his opponent.
He could barely walk at the end of the fifth game and had to be helped to his chair before accepting reality and calling it quits.
Earlier, 24-time Grand Slam winner Djokovic was given a mighty scare by the 150th-ranked Hanfmann.
The Serb fired two aces to start, delighting the crowd, but soon ran into trouble as Hanfmann found his range.
The German broke in the third game and held serve after that to clinch the first set.
"I was just outplayed by a better player for a set and a half –- I was hanging by a rope to stay in the match," Djokovic said.
Neither player was able to take control of a gruelling second set, until a series of unforced errors from Hanfmann in the 12th game gave Djokovic the opening he needed.
Sweating in 28C humidity at 9:00 pm, the 24-time Grand Slam champion then broke in the fourth game of the third set as his 33-year-old opponent's precision dropped.
Cheered on by a stadium full of adoring fans, Djokovic held his resolve to take the third set after Hanfmann hit the ball out.
"I had to dig in really, really deep to come out from this match as a winner, and I think the energy and support of the crowd really got me out," Djokovic said.