Serena Williams's long-awaited return to competitive tennis was left in the balance on Wednesday after doubles partner Victoria Mboko was forced to retire in her opening singles match during the WTA tour event at Queen's Club.

Tennis great Williams, 44, made her eagerly-anticipated comeback at the London venue on Tuesday, securing a win alongside Canadian teenager Mboko in their first doubles match

The duo defeated Nicole Melichar-Martinez and Erin Routliffe.

They are now scheduled to face Leylah Fernandez and Laura Siegemund on Thursday in the grass-court event, a warm-up for Wimbledon.

Mboko, who received a bye into the round of 16 for the singles event, was down a set but leading Karolina Pliskova 4-3 in the second when she slipped behind the baseline trying to return a shot.

The stumble effectively forcing her into doing the splits, drawing a gasp from the crowd.

Mboko was visibly upset as she spoke to the attending medical staff.

She got to her feet but the official reason subsequently given for her retirement from the match was a left knee injury, with Mboko heard to say on a television microphone "there is no stability right now."

Mboko buried her face behind a towel as she continued to consult her team, before the umpire eventually announced her retirement, with the crowd giving the 19-year-old a sympathetic reception. (AFP)



Edited by Cecil Wong