|Venue: Flushing Meadows, New York Dates: 28 August-10 September|
|Coverage: Daily live text and radio commentaries across the BBC Sport website, app, BBC Radio 5 Live and 5 Sports Extra|
Iga Swiatek began her US Open title defence with an emphatic first-round victory as eighth seed Maria Sakkari fell to a surprising loss.
World number one Swiatek breezed to a 6-0 6-1 win over Sweden’s Rebecca Peterson in 58 minutes.
Sakkari had a day to forget on Court 17 as she was knocked out by world number 71 Rebeka Masarova of Spain.
Elsewhere, Beatriz Haddad Maia beat 2017 champion Sloane Stephens and Elena Rybakina cruised into the second round.
Rybakina beat Ukraine’s Marta Kostyuk 6-2 6-1 despite struggling in the build-up to the tournament with a shoulder injury.
‘I was happy on the court’ -Swiatek
Swiatek has won both previous meetings with world number 86 Peterson and came through this encounter on Arthur Ashe Stadium in imperious style.
The 22-year-old Pole, who is bidding to win her fifth Grand Slam title, will face Daria Saville of Australia in the second round.
Swiatek said: “I wanted to start the tournament with everything I was focusing on. I was happy to play a great game, with all the pressure and expectations, I was happy on the court.
“I feel like everything that is going on around us is taking away our attention and what we want to achieve with our games and careers.
“I want to remind myself that I want to develop as a player. The numbers and stats don’t really matter to me. I’m just trying to focus on my performance.”
Sakkari shocked and Rybakina through
Greece’s Sakkari became the first top 10 player to fall in the women’s draw.
Sakkari raced to a 4-1 lead in the first set but her unseeded opponent Masarova responded in fine fashion to claim a 6-4 6-4 win and hand Sakkari her third consecutive first-round Grand Slam loss.
American Stephens, champion in 2017, was beaten by Brazilian 19th seed Haddad Maia 6-2 5-7 6-4 with five breaks traded in a thrilling deciding set on Louis Armstrong Stadium.
Haddad Maia, a semi-finalist at the French Open, is through to the second round at Flushing Meadows for just the second time.
There were more routine wins for other seeded players on the opening day.
Victoria Azarenka made light work of Frenchwoman Fiona Ferro in their match at the Louis Armstrong Stadium.
The 18th seed, who reached the US Open final in 2012, 2013 and 2020, wrapped up a comprehensive 6-1 6-2 victory over the world 190.
Elsewhere, Czech 10th seed Karolina Muchova clinched a 6-4 6-0 win over Storm Sanders of Australia, while 15th seed Belinda Bencic of Switzerland eased past Kamilla Rakhimova 6-2 6-4.
And unseeded American Danielle Collins, finalist at last year’s Australian Open, defeated Linda Fruhvirtova 6-2 6-0.