Defending champion Naomi Osaka claimed a straight-set victory at the US Open on her first Grand Slam appearance since withdrawing from the French Open.
The Japanese third seed, 23, ground down Czech world number 87 Marie Bouzkova for a 6-4 6-1 first-round win.
She will play world number 145 Olga Danilovic of Serbia next.
Osaka withdrew from Roland Garros in May, revealing she had “suffered long bouts of depression” since winning her first major title at the 2018 US Open.
The four-time major champion decided not to play at Wimbledon in June but returned for the Tokyo Olympics, where she lost in the third round.
Bouzkova showed impressive early resistance in New York, but Osaka eventually got a break at 5-4 up to seal the first set.
The 2021 Australian Open winner came into the tournament having won only three matches in the past three months but looked to have recovered her form as she overpowered and outmanoeuvred her opponent in the second set.
After her win, Osaka said she felt “really comfortable” playing on Arthur Ashe Stadium again, adding it was “kind of crazy” to play in front of fans after the tournament was held behind closed doors in 2020 because of the coronavirus pandemic.
“Last year when we didn’t have a crowd I know it felt quite lonely for me,” she said.
“I’m just really glad to see little kids in the audience and of course grown-ups too. To be playing the first night match is something I’ve never done before so I’m just glad I won.”
Osaka celebrated her win by running over to a young fan and sharing a souvenir to remember her visit to Flushing Meadows.
“I heard her and she was so cute,” she explained.
“Thank you for cheering me on. In the Olympics we got little pins that we were supposed to pass around to other players.
“I wasn’t there for a long time so I have a couple in my bag left over. I thought it would be a nice memory.”
Several other Grand Slam winners secured a place in the second round on the tournament’s opening day.
Former world number one Simona Halep made a winning return to Grand Slam tennis after missing the French Open and Wimbledon with a calf tear, beating Italian Camila Giorgi 6-4 7-6 (7-3).
Two-time major winner Garbine Muguruza claimed a 7-6 (7-4) 7-6 (7-5) victory against Donna Vekic, while 2017 US Open champion Sloane Stephens battled past fellow American Madison Keys to win 6-3 1-6 7-6 (9-7).
French Open champion Barbora Krejcikova sealed her place in the second round by beating Australian Astra Sharma 6-0 6-4.
Belarusian second seed Aryna Sabalenka was also victorious as she bids for a first major singles title, winning 6-4 6-7 (4-7) 6-0 against Serb Nina Stojanovic, while Ukrainian fifth seed Elina Svitolina beat Canada’s Rebecca Marino 6-2 6-3.
Stephens, 28, will play compatriot Coco Gauff next after the 17-year-old came from behind to beat Poland’s Magda Linette 5-7 6-3 6-4.
Two-time major champion and last year’s runner-up Victoria Azarenka of Belarus also advanced with a 6-4 6-0 win over Czech Tereza Martincova, while German three-time Grand Slam champion Angelique Kerber came back from 3-5 down in the third set to beat Ukraine’s Dayana Yastremska 3-6 6-4 7-6 (7-3).
World number one Ashleigh Barty begins her campaign on Tuesday.