Madison Keys pulled out of her Wimbledon third-round clash with Yaroslava Shvedova on Monday due to injury.

The hard-hitting American teenager was due to begin a second-set tie-break on Court 12, having dropped the first set and squandered a chance to serve for the second when 6-5 in front on Saturday evening.

Her withdrawal meant Kazakh player Shvedova, who led 7-6 (9/7) 6-6, went through to a fourth-round clash with Ana Ivanovic or Sabine Lisicki.

Ivanovic and Lisicki were preparing to resume their third-round tussle, in which Lisicki led 6-4 1-1, on Court One.

Wimbledon officials announced a left thigh injury had forced 19-year-old Keys to withdraw.

She was observed at the All England Club on Monday morning with heavy strapping on her left leg, having suffered the injury during the match and called for a trainer in the fading light at 9.25pm on Saturday, prior to dropping serve when bidding to level the match.

The exit of Keys means there are no Americans left in the women's singles at the start of the second week, with top seed Serena Williams having been a surprise third-round casualty on Saturday when she was eliminated by French player Alize Cornet.

Keys had come to Wimbledon with the boost of winning the Eastbourne title behind her, having beaten Angelique Kerber in the final after breezing by Britain's Heather Watson in the semi-finals.

It was a first career title for a player many expect to reach the top 10, and lifted her to a career-high ranking of number 30.

But Keys was in tears as she received court-side treatment on Saturday evening, already fearing the worst.

Keys expects to be sidelined for only a fortnight.

She said: "Before the match I had the other leg taped. That was just precaution. It was tight. I didn't want it to go.

"In the middle of the second set I kind of felt something a little bit. I was thinking, 'Try to get through the set, maybe it could finish, have the next day to recover, try to get better'.

"Then I think it was the 3-2 game, I was serving. I just felt it really go. After that it was pretty painful.

"I have a muscle strain in my adductor. It's not terrible, not really long recovery time. But they were warning me it could get worse."

Keys acknowledged she had been emotional on leaving the court on Saturday evening, and said: "It was more like I was trying not to bawl my eyes out. I think there were some tears.

"It's definitely not how I want to be leaving Wimbledon, but it happens. You just have to take it in your stride, just accept it, just try to get better."