HIGHLIGHTS-Tennis-US Open day seven

I felt no control suddenly," the 22-year-old Pole told reporters. The four-times Grand Slam winner will lose her world number one ranking to Aryna Sabalenka, while Ostapenko next faced Coco Gauff.

Highlights of the seventh day of the U.S. Open at Flushing Meadows on Sunday (times GMT): 0358 OSTAPENKO KNOCKS OUT SWIATEK

Defending champion and top seed Iga Swiatek crashed out with a 3-6 6-3 6-1 fourth-round defeat by 2017 French Open winner Jelena Ostapenko of Latvia. "I'm just surprised that my level changed so drastically because usually when I play bad, I play bad at the beginning, then I kind of catch up or just problem solve... I felt no control suddenly," the 22-year-old Pole told reporters.

The four-times Grand Slam winner will lose her world number one ranking to Aryna Sabalenka, while Ostapenko next faced Coco Gauff. READ MORE

Swiatek bundled out of US Open, Djokovic marches on U.S. Open order of play on Monday

Ostapenko dumps defending champion Swiatek out of U.S. Open

With 'nothing to lose', Fritz

guns for Djokovic upset at U.S. Open Djokovic enjoys drama-free win to reach U.S. Open quarters

Wozniacki says she is 'on the right track' despite U.S. Open exit Gauff outlasts Wozniacki to reach U.S. Open quarter-finals

Cirstea beats Bencic to reach first Grand Slam quarters in 14 years Shelton first through to quarters as action heats up at U.S. Open

Alcaraz passes test while Medvedev works U.S. Open graveyard shift 0143 DJOKOVIC THROUGH TO QUARTERS

Second seed Novak Djokovic secured his place in the quarter-finals with a 6-2 7-5 6-4 win over Borna Gojo of Croatia. The 36-year-old Serbian next faces American Taylor Fritz.

0026 FRITZ OVERCOMES STRICKER American Taylor Fritz, seeded ninth, booked his place in the quarter-finals after a battling 7-6(2) 6-4 6-4 win over Swiss Dominic Stricker to reach the last eight for the first time in his career.

"That was a battle, a really, physical, tight three sets that really came down to a couple of points here and there. I've had a lot of trouble at Slams, and there's no other place I'd rather do it," Fritz said. 2151 TIAFOE SWEEPS PAST HIJIKATA

American Frances Tiafoe, the 10th seed, comfortably advanced to the quarter-finals with a 6-4 6-1 6-4 victory over Australian Rinky Hijikata. He will face compatriot Ben Shelton in the last eight. 2129 GAUFF DOWNS WOZNIACKI

Sixth seed Coco Gauff ended the run of former world number one and two-time U.S. Open finalist Caroline Wozniacki 6-3 3-6 6-1. The American will face the winner of the match between Jelena Ostapenko and Iga Swiatek in the quarter-finals. "Caroline is back and it looks like she never left, the level that she played today is amazing and she's being an inspiration for me. I remember when I saw her win the Australian Open, to play with her is an honour," Gauff said.

1929 CIRSTEA UPSETS BENCIC Romanian Sorana Cirstea upset Olympic champion and Swiss 15th seed Belinda Bencic 6-3 6-3 to advance to the quarter-finals, where she will face Czech 10th seed Karolina Muchova.

"It's incredible, I always dreamed of being here, it's been many years where I have worked hard but wasn't rewarded, but in the end, if you keep working it pays off," Cirstea said. 1902 SHELTON KNOCKS PAUL OUT

Ben Shelton beat 14th seed Tommy Paul 6-4 6-3 4-6 6-4 in an all-American clash at Arthur Ashe Stadium, sending the 20-year-old into the quarter-finals. 1743 MUCHOVA BEATS WANG

Czech Karolina Muchova, the 10th seed, beat Xinyu Wang of China 6-3 5-7 6-1 to advance into the U.S. Open quarter-finals for the first time.