Coco Gauff, a fan favourite at previous Grand Slam appearances, said afterwards she did not think the absence of spectators in New York had hampered her performance.
Naomi Osaka defeated Lativia's Anastasija Sevastova to reach the Brisbane International semi-finals.
Serena Williams needed just 66 minutes to dispatch the 19th-seeded Anastasija Sevastova to reach her ninth US Open final.
Anastasija Sevastova will face either 23-time major champion Serena Williams or eighth-seeded Czech Karolina Pliskova.
Caroline Wozniacki's father Piotr had been quoted in national media as suggesting that his daughter was unlikely to play beyond next year
Caroline Wozniacki, who beat Anastasija Sevastova in the quarterfinals, will face second seed Angelique Kerber in the US Open women's singles semifinal
Three years after quitting tennis due to depression and injuries, Anastasija Sevastova on Sunday became the first Latvian woman to reach a Grand Slam quarter-final in 22 years