Former world number one Simona Halep qualified for the second round of the US Open with a 6-4 7-6(7-3) victory over Camila Giorgi.
Halep produced six aces compared to her Italian Open as she dominated with her service game, and it was with that dominance that she was able to earn victory.
The Romanian took all three of the break points she forced, while her less ruthless opponent had six break points but could only take two of them.
'A night I’ll always remember' - Henman on Raducanu celebrations in New York
- Osaka vows to celebrate herself and her accomplishments more ahead of US Open
- 'Murray has to prove he belongs' - Wilander
- 'My dream was to meet him' - Tsitsipas on collab with Dudewithsign
Halep had been forced to miss both the French Open and Wimbledon earlier in the season as she battled a tear in her left calf, but now appears fit enough to compete in America.
Kaia Kanepi pulled off an upset as she came back to defeat 31st seed Yulia Putintseva 2-6 7-6(7-4) 6-2.
Ann Li lost 7-6 6-1 to Slovak Kristina Kucova as she fell out of her home Grand Slam.
Mayar Sherif took a one-set lead against Anhelina Kalinina on Court 9 but the Ukrainian rallied to win convincingly 4-6 6-1 6-1.
Canada's Leylah Annie Fernandez was a 7-6(7-3) winner over Croatia's Ana Konjuh.
Home favourite Danielle Collins defeated Spaniard Carla Suarez Navarro 6-2 6-4.
32-seeded Ekatrina Alexandrova comfortably beat Italian Sara Errani 6-3 6-2.
Britain's Heather Watson was easily swept aside by Kaja Juvan 6-1 6-4. 19th seed Elena Rybakina defeated Aliaksandra Sasnovich 6-2 6-3.
Another Briton suffered an early exit as Harriet Dart lost to France's Caroline Garcia 6-7(6-8) 6-4 6-2.
Germany's Andrea Petkovic survived some late resistance from Irina-Camelia Begu to win 6-2 7-6(7-3).
Maria Camila Osorio Serrano eased past Ivana Jorovic 6-2 6-2 in one of the day's last matches.
‘Going to be tough’ – Why hard-court king Djokovic will be pushed at US Open
Raducanu donates US Open final outfit to Tennis Hall of Fame
'The younger generation has taken over' - Becker hails 'Dame Emma Raducanu'