Fourth seed Naomi Osaka overcame a scare to beat fellow Japanese player Misaki Doi in three sets and avoid a major shock in the US Open first round.
Osaka, who won the first of her two Grand Slams at Flushing Meadows in 2018, wobbled in the second set before recovering for a 6-2 5-7 6-2 victory.
Elsewhere, teenager Coco Gauff’s hopes of another Grand Slam run were ended by 31st seed Anastasija Sevastova.
But top seed Karolina Pliskova and sixth seed Petra Kvitova advanced.
Osaka, 22, withdrew from the Western and Southern Open final on Saturday with a left hamstring injury, saying afterwards she was “stressing” about her fitness going into the Grand Slam.