WIMBLEDON, England — Ash Barty's winning streak is over, and so are her chances of winning a second straight Glam Slam title.

The top-ranked Australian had won 15 matches in a row, including the French Open title, but she lost to Alison Riske 3-6, 6-2, 6-3 at Wimbledon on Monday, giving the unseeded American a spot in the quarterfinals of a major tournament for the first time.

"I haven't been starting out fantastic in all my matches, but I knew I had the confidence that if I could manage my service games I was going to get looks on her serve," said Riske, whose best previous showing was reaching the third round at Wimbledon and the fourth round at the 2013 U.S. Open. "I had to play aggressive. I had to take it to Ash."

Barty was playing her first tournament as the No. 1-ranked player, and she started off by winning points with her serve against Riske.

In the opening service game, the top-seeded Barty won all four points with aces. She won two more points in her next game with aces, as well. She finished the match with 12 of them.

But Riske took her chances when she got them, breaking Barty four times on four attempts, including to take a 5-3 lead in the deciding set before serving it out.

Riske will next face either Serena Williams or Carla Suarez Navarro on Tuesday in the quarterfinals.

Also, No. 8 Elina Svitolina beat No. 24 Petra Martic 6-4, 6-2, and Zhang Shuai defeated Dayana Yastremska 6-4, 1-6, 6-2.

Svitolina won six straight games from 4-4 in the first set. Martic called for medical treatment on her left leg after the first game of the second set and her movement appeared to be hampered the rest of the way. She asked for treatment again at 4-1.

Later on "Manic Monday," Williams, 15-year-old sensation Coco Gauff and the men's Big Three of Roger Federer, Rafael Nadal and Novak Djokovic are on the schedule as Wimbledon resumes after its traditional day off.

Gauff will try to prolong her magical Grand Slam debut when she meets former No. 1 Simona Halep. That match on No. 1 Court follows seven-time Wimbledon champion Williams against Navarro.

The top three seeded men — Djokovic, Federer and Nadal — all face opponents who never have been to the second week at Wimbledon.