SERENA WILLIAMS’ doubles comeback at Queen’s is in major doubt after her partner Victoria Mboko was forced to retire from her singles match with injury.

Mboko, 19, was handpicked by Williams for her return to professional tennis this week.

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Victoria Mboko slips on the grass at Queen’s Credit: Getty

Mboko, 19, is spoken to by the chair umpire and opponent Karolina Pliskova Credit: Getty

The pair knocked out No3 seeds Nicole Melichar-Martinez and Erin Routliffe in front of a raucous West London crowd on Tuesday.

Williams and Mboko are scheduled to take on Laura Siegemund and Leylah Fernandez in round two on Thursday evening.

But their participation has been left hanging by a thread after Mboko suffered a nasty fall.

The Canadian trailed former Wimbledon finalist Karolina Pliskova 6-2 3-4 when she carved out three break points on Andy Murray Arena.

Mboko buried her head in her towel as she assessed by doctors Credit: Getty

The teenager was devastated as she made her way off the court Credit: Getty

Pliskova saved the first two, before launching a winner past Mboko on the third.

Standing way behind the baseline, Mboko suffered a nasty slip, appearing to twist her knee in the process.

The moment prompted a sharp intake of breath from crowd, with the chair umpire and even Pliskova going over to check on the downed teenager.

After around a minute Mboko gingerly got to her feet, making her way over to her chair.

Mboko played with Serena Williams on the American’s comeback on Tuesday Credit: Getty

The inter-generational duo are due on court again on Thursday Credit: Shutterstock Editorial

The No3 seed was then assessed by a doctor, and appeared to be in tears as she buried her head in her towel.

Before long her decision was made, Mboko deciding to pull the plug on the match – officially retiring with a “left knee injury”.

Williams could theoretically still take to the court tomorrow, should Mboko’s slip not be as bad as first feared.

But the American cannot substitute in another partner, meaning that if Mboko is not fit they will have to withdraw as a pair.

Williams had given herself a “C-minus” report upon her return as she spoke to the press alongside Mboko on Tuesday.

On her decision to come back, she added: “I had nothing better to do.

“I got tired of sitting at home. My kids are out of school for the summer, so why not?”

Williams has not yet confirmed whether she will play at Wimbledon, but she has taken a doubles wildcard for the WTA 500 event in Berlin next week.

Earlier today The Times reported that Williams has selected Karolina Muchova to be her partner in Germany.

On her SW19 prospects, Williams added: “It’s just a day at a time. I still have a little time to decide, and they have been great about giving me that space and time to decide.”

Earlier today, Iva Jovic opened play by defeating last week’s Birmingham champion Alexandra Eala 6-2 6-2 in a next-gen clash.

Last year’s beaten Wimbledon finalist Amanda Anisimova, playing in London for the first time since her 6-0 6-0 defeat in last year’s SW19 showpiece, then comfortably beat Laura Siegemund 6-1 6-3 in a match interrupted by rain.

Iva Jovic made a winning debut at the Queen’s Club Credit: Shutterstock Editorial

Amanda Anisimova comfortably defeated Laura Siegemund on her return to Andy Murray Arena Credit: Getty