LONDON — Serena Williams’ doubles campaign at Queen’s Club could be over after one match.

Victoria Mboko, the American star’s doubles partner, sustained a knee injury in her singles match against Karolina Pliskova.

Williams and Mboko had won their opening doubles match — in the 44-year-old Williams’ return to professional tennis nearly after four years away from the sport — and are scheduled to play again Thursday.

The 19-year-old Canadian slipped behind the baseline and immediately grabbed her left knee while facing Pliskova. Mboko lost the first set 6-2 and was up 4-3 in the second and trying to break with Pliskova serving at deuce.

Mboko got up on her own but then told a physiotherapist that there was “no stability right now.”

She walked gingerly to her bench and put a towel to her face as she sat down. Minutes later, she retired from the match.

Williams previously had announced she also will play doubles at the Berlin Open.