Bianca Andreescu has revealed she tore ankle ligaments and faces time on the sidelines after her excruciating injury blow at the Miami Open.

Former US Open champion Andreescu, who in 2019 beat Serena Williams in what proved to be the American great's last grand slam final, is set to miss at least the start of the clay-court season.

The Canadian 22-year-old was enjoying an excellent run in the Miami event, knocking out Emma Raducanu, Maria Sakkari and Sofia Kenin en route to the last-16 stage.

She dropped the first set against Ekaterina Alexandrova on Monday but was an early break to the good in the second when injury struck, forcing her to abandon that fourth-round match.

Andreescu howled in pain on the court after suffering the ankle blow and needed to be taken away in a wheelchair.

She joked the day after: "Woke up with a brace on my foot… anyone know what happened?"

Now she knows exactly what happened, and the news is not particularly good.

Andreescu posted on Twitter: "Results show that I've torn 2 ligaments in my left ankle. It's tough to say exactly how long it will take, but let's just say it could've been much worse!!

"I'm going to take it day by day, and I am optimistic that with the right work, rehab, and preparation, I'll be back on court soon. Rehab process has already started and will continue to give updates."

Andreescu has suffered a string of injuries since becoming a teenage grand slam winner. She sits 31st in the WTA rankings, having been as high as number four in October 2019.

Miami marks the end of a hardcourt swing on the tour, with clay set to take over for two months, starting in Charleston at a WTA 500 event next week.