Canadian 15th seed Bianca Andreescu beat former Australian Open champion Caroline Wozniacki in the third round of the US Open.

The 19-year-old, playing at Flushing Meadows for the first time, won 6-4 6-4 in a match featuring 10 service breaks.

Andreescu, who has won titles in Toronto and Indian Wells this year, will face American Taylor Townsend in the next round.

Elsewhere, Dutch seventh seed Kiki Bertens lost to German Julia Gorges.

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Bertens, a former Wimbledon quarter-finalist last year, fought off four match points before Gorges won 6-2 6-3.

Gorges, seeded 26th, will face Donna Vekic in the fourth round after the Croat beat Kazakh Yulia Putintseva 6-4 6-1.

World number 116 Townsend knocked out Wimbledon champion Simona Halep in the second round and beat Romanian Sorana Cirstea 7-5 6-2 on Saturday.

Meanwhile, Latvian world number 77 Jelena Ostapenko, a former French Open champion, lost 6-3 7-5 to American Kristie Ahn, who had never won a main draw singles match at a Grand Slam before.

Ahn faces Belgian 25th seed Elise Mertens in the fourth round. The former Australian Open semi-finalist won 6-3 6-3 against German Andrea Petkovic, ranked 88th.

Ukrainian fifth seed and Wimbledon semi-finalist Elina Svitolina stormed past Ukrainian 32nd seed Dayana Yastremska to win 6-2 6-0 to set-up a fourth-round tie with American 10th seed Madison Keys.

Swiss 13th seed Belinda Bencic was given a walkover to the next round after Estonian opponent Anett Kontaveit retired with illness prior to their match on Louis Armstrong.