Serena Williams' doubles campaign at Queen's has been curtailed as her playing partner Victoria Mboko has withdrawn with a left knee injury.

The 23-time Grand Slam singles champion, 44, made her return to tennis on Tuesday after almost four years away from the sport.

The pair had been scheduled to play their quarter-final on Thursday but Mboko, 19, suffered a nasty fall in her singles match on Wednesday, which forced her to retire from the match.

Trailing 6-2 3-4 against Karolina Pliskova, the Canadian teenager cried out in pain as she went down clutching her knee and she limped off the court in tears.

It means her compatriot Leylah Fernandez and Germany's Laura Siegemund, who they were scheduled to face in the doubles on Thursday, advance to the semi-finals.

"What a fun and memorable week at the HSBC Championships. Thank you to everyone who made it so special," Williams posted on Instagram.

"Vicky Mboko, you're an incredible talent and you'll be back out there in no time.

"Wishing you a speedy recovery."

Williams returned with a winning performance on Tuesday as she and Mboko won 7-6 (7-2) 6-2 to upset third seeds Erin Routliffe and Nicole Melichar-Martinez.

Playing 1,375 days after her last competitive match, Williams - one of the greatest players of all time - didn't look a touch out of place as she rediscovered her powerful serve and groundstrokes.

The extent of Mboko's injury has not yet been confirmed but there are concerns that the world number nine could miss Wimbledon, which starts on 29 June.