London, June 10 -- Serena Williams' doubles campaign at Queen's is in jeopardy after her partner Victoria Mboko suffered a knee injury in her singles match against Karolina Pliskova.
The 23-time Grand Slam champion, 44, made her return to tennis on Tuesday after almost four years away from the sport, playing doubles alongside Mboko.
The pair knocked out the third seeds, but there is now uncertainty around their quarter-final match on Thursday after Mboko suffered a nasty fall, according to BBC Sport.
The 19-year-old Canadian cried out in pain as she slipped while trying to reach a forehand by Pliskova and went down clutching her left knee.
Mboko was able to get to her feet and walk back to her chair a few moments later, but she was visi...