ONDON, United Kingdom (AFP) — Serena Williams’ bid to win the Queen’s Club doubles title on her return to tennis came to a premature end on Thursday after the American legend’s partner Victoria Mboko was forced to withdraw from the tournament.

Williams sensationally returned to action on Tuesday for the first time in four years, partnering with Mboko for a straight sets victory over Nicole Melichar-Martinez and Erin Routliffe in the first round.

The pair were due to play Leylah Fernandez and Laura Siegemund in the quarterfinals of the grass-court event in west London on Thursday.

But Mboko pulled out just hours before the last eight clash after failing to recover from a left knee injury suffered in the second set of her singles match against Karolina Pliskova on Wednesday.

World No. 9 Mboko, who was injured after slipping on the court, was unable to finish that match.

The 19-year-old Canadian was visibly upset following her injury, which effectively forced her into the splits, and was heard telling physios “there is no stability right now.”

Mboko opted not to risk aggravating the injury by playing in the doubles with Williams.

Tournament organizers confirmed Mboko’s withdrawal from the doubles, leaving Williams to wait to continue her comeback in the Berlin Open doubles next week.

Williams is reportedly set to play alongside Karolina Muchova in Berlin, with the 23-time Grand Slam champion still pondering whether to take her comeback tour to Wimbledon.

She is yet to reveal if she will play any singles events during her shock return to action, but told reporters at Queen’s earlier this week that she hadn’t ruled out featuring in the Wimbledon doubles.

Williams would need a wildcard from Wimbledon chiefs to feature at the All England Club since she is not ranked high enough to earn automatic entry into the tournament.

The seven-time Wimbledon singles champion also won six doubles titles alongside her sister Venus at the grass-court Grand Slam.