Fourth seed Elina Svitolina overcame a scare to beat world number 42 Katerina Siniakova in the US Open first round.
The Ukrainian fought back from a disappointing second set to win 6-0 6-7 (5-7) 6-3 on Louis Armstrong Stadium.
Svitolina had been in control of the match before rain intervened on Tuesday, and she struggled for rhythm when play restarted on Wednesday.
"Today was a little bit of a mess in my head and it was very tough to keep the focus," she told Eurosport.
The world number four will face Evgeniya Rodina in the second round, after the Russian beat Canada's Eugenie Bouchard 7-6 (7-2) 6-1.
Svetlana Kuznetsova, who won at Flushing Meadows in 2004, saved three match points to prevail against Marketa Vondrousova in an entertaining encounter on Grandstand Court.
The 18-year-old Vondrousova was left in tears as she lost the third set tie-break after struggling with cramp.
Fourteenth seed Kristina Mladenovic, who has gone out in the first round in her past three tournaments, continued the pattern as she lost in straight sets to Romania's Monica Niculescu.
American 20th seed Coco Vandeweghe overcame a first-set loss to beat compatriot Alison Riske 2-6 6-3 6-4, despite a mixed performance that saw her make 45 unforced errors, while Agnieszka Radwanska registered a 6-4 7-6 (7-3) win over Petra Martic.
Svitolina overcomes slow start as match resumed
Svitolina led the second set tie-break 2-1 but lost the first four points when play resumed as Siniakova forced a deciding set.
The Czech broke Svitolina straight away in the third set but grew frustrated as the match progressed, making 17 unforced errors to Svitolina's seven as the Ukrainian found her feet.
She broke Siniakova in the sixth game of the third set and went on to serve out the match in two hours 22 minutes.
"It was a little bit unlucky to stop yesterday because I was playing good and feeling good. She had nothing to lose," Svitolina added.