Madison Keys revealed Monday that she suffered a hamstring injury of unknown severity during Sunday's fourth-round match at Wimbledon against Jasmine Paolini.

Keys, the No. 12 seed, was tied a set apiece with the seventh-seeded Italian. Keys led 5-2 in the decider set and was serving but could not close out the match. Paolini had cut her deficit to 5-4 when Keys left the court for a medical timeout and returned with her left thigh taped.

Her movement restricted, Keys saw Paolini win her fourth consecutive game for 5-5, and the American cried in pain following the game. Keys retired during the 11th game.

"Well... The ending of yesterday's match was probably one of my toughest moments ever on court," Keys posted to social media Monday.

"Unfortunately during the match, I injured my hamstring. I'll be getting an MRI soon to see exactly what happened and what the severity of the injury is. I have a lot of mixed emotions that my Wimbledon ended like this and really appreciate all the nice messages I've gotten.

"Time to go home and get better."

Keys, who was vying for her first career Grand Slam win, was on the cusp of making the second straight Wimbledon quarterfinals. It is the only Grand Slam event where she has not reached the semifinals.

Keys was named to the U.S. Olympic tennis team last month but decided to not compete in Paris.

--Field Level Media