From first ball, the WTA stars were pushed hard in Flushing Meadows, including Angelique Kerber.
The No.6-seeded Kerber fought off a point for a 5-3 third set deficit to make it past Ksenia Pervak.
Simona Halep, the No.2 seed, had to rally from a set down to beat American wildcard Danielle Collins.
Kimiko Date-Krumm didn't just have to battle Venus Williams, she had to survive a very pesky bee.
The bee literally wouldn't leave her alone - it took a gang of ballkids to remove the tough guy.
Date-Krumm would push Williams to a third set but the No.19-seeded American prevailed, 2-6, 6-3, 6-3.
Daniela Hantuchova, a two-time quarterfinalist at the US Open, rallied past Romina Oprandi in three.
Sloane Stephens, the No.21 seed, didn't need three sets to get past WTA Rising Star Annika Beck.
The traditional Opening Ceremony took place before the night matches began - baby you're a firework...
Sara Errani, a semifinalist here in 2012 and this year's No.13 seed, edged Kirsten Flipkens at night.
Caroline Wozniacki, a former finalist here and the No.10 seed, also got through her first match.
And Maria Sharapova, the No.5 seed but No.1 on the Road To Singapore leaderboard, wrapped up Day 1.