Upsets on Day 6 at US Open: French Open champion ousted

French Open champion Ostapenko out of US Open

French Open champion Jelena Ostapenko was knocked out of the US Open third round, losing 6-3, 6-2 to Russian Daria Kasaktina after hitting a massive 38 unforced errors on Saturday.

The Latvian 12th seed, who broke into the limelight in June when she blasted her way to the Roland Garros title, got off to a fast start but the unseeded Kasaktina mixed her game with sliced backhands and chopped forehands to slow her opponent down.

The plan worked as after winning the first three games, Ostapenko grew frustrated and bowed out when she netted a backhand on the second match point at the end of a lung-busting rally.

Ostapenko complained of nausea and illness during the match.

"I was not feeling 100 per cent today, I was not feeling good already at the beginning of the day. I couldn't give my 100 per cent today, like not my best," she said.

It has been, however, a breakthrough year for the 20-year-old Ostapenko after she reached the third round at the Australian Open and the last eight at Wimbledon after lifting the Suzanne Lenglen Cup in Paris.

"In general, I think it was not bad. Of course, I expected to play better here, but unfortunately, couldn't give my best today," she said.

Kasaktina seized the opportunity and shook her early nerves to reach the last 16 of a Grand Slam for the first time.

"In the beginning I was a little bit nervous but I tried to stay focused and play my game and it paid off," said Kasaktina, who faces Estonian qualifier Kaia Kanepi for a place in the quarter-finals.

Monfils injured yet again as he loses to Goffin in New York

Gael Monfils suffered yet another injury as he retired from his third-round match against Belgian ninth seed David Goffin at the US Open.

The Frenchman had dropped the first set 7-5 before losing interest in the match in the second as he appeared to suffer from a leg injury.

The 18th seed quickly fell 5-0 behind, finally requesting the trainer on court for a right thigh massage. He won one game before throwing in the towel.

Monfils has suffered an Achilles injury, a knee injury and an akle injury this season.

Goffin next faces Bosnian Damir Džumhur or Russian Andrey Rublev for a place in the last eight.