San Francisco Frontiers - Alexander Zverev: Other recent Grand Slam injuries

Here, AFP Sport takes a look at other recent injury retirements at Grand Slam tournaments:

Rafael Nadal: 2018 US Open semi-finals

-- Nadal was chasing an 18th Grand Slam title as the defending champion at the US Open four years ago.

Blocking his path to the final was Juan Martin del Potro, who he had beaten in both the French Open semi-finals and Wimbledon quarter-finals in 2018.

But Nadal had spent more time on court than any other player that fortnight at Flushing Meadows and a right knee injury proved too difficult to manage.

The Spaniard called it quits after losing the second set to trail 7-6, 6-2.

"Of course, it's not the best way to win a match," said Del Potro, who lost to Novak Djokovic in the final.

"I love to play against Rafa because he's the biggest fighter in this sport. I don't like to see him suffering on the court."

Bethanie Mattek-Sands: 2017 Wimbledon second round

-- The colourful American collapsed to the court after dislocating her kneecap after slipping while moving to the net for a volley in her match against Sorana Cirstea.

Mattek-Sands was left screaming "Please, help me, please, please" in scenes so distressing that TV cameras panned away from the stricken star.

"I needed help getting in and out of bed," she said at the following year's French Open. "If I needed to go to the shower or go to the bathroom, I needed someone to help me get there."

She returned to tennis the following year and has since won two US Open mixed doubles titles to take her Grand Slam tally to nine.

David Goffin: 2017 French Open third round

-- Belgian Goffin was forced to retire from his third-round tie against Horacio Zeballos in the first set after his ankle became caught up in the court covers.

His right foot got horribly jammed beneath the rolled-up covers before he tumbled into the wall and a linesman's chair.

An MRI scan revealed no fracture and Goffin was able to return six weeks later, going on to reach the ATP Finals final later that year.

David Nalbandian: 2006 French Open semi-finals

-- Argentinian Nalbandian was the last man before Zverev to retire from a semi-final or final at Roland Garros 16 years ago.

He was level at one-set-all with Roger Federer, but trailing 5-2 in the third set, when he retired with an abdominal injury.

"It doesn't usually happen that someone actually starts playing a match and then gives up halfway through," Federer, who lost to Nadal in the final, said.

Nalbandian, the 2002 Wimbledon runner-up, had been leading then-world number one Federer 6-3, 3-0 earlier in the match.

Q.Taylor--SFF