Coverage: Online radio commentary of Heather Watson, plus live radio and text commentary on every Andy Murray match and selected others.
Serena Williams and Rafael Nadal lived up to their billing with victories in the first of this year’s US Open night sessions.
Top seed Williams needed just 30 minutes to begin her bid for a first calendar Grand Slam as Vitalia Diatchenko retired at 6-2 2-0 down.
Nadal, seeded eighth, saw off 18-year-old Borna Coric 6-3 6-2 4-6 6-4.
World number one Novak Djokovic went through, but fourth seed Kei Nishikori was beaten.
The Japanese player, last year’s runner-up, lost 6-4 3-6 4-6 7-6 (8-6) 6-4 to Frenchman Benoit Paire.
“It’s always very sad to lose in the first round, but I think he was playing good tennis so I don’t think I played bad,” Nishikori said.
Kei Nishikori lost to Marin Cilic in last year’s US Open final
Djokovic swept past Brazil’s Joao Souza 6-1 6-1 6-1 to reach round two, and Nadal showed glimpses of his best form in beating Croatia’s Coric.
The Spaniard, 29, dominated the first two sets and then saw off a resurgent Coric in the fourth with a rasping forehand to earn the decisive break.
“I think I started playing well,” Nadal said. “The first two sets was a very high level for me, then I got a little bit tired.
“The conditions here are very humid, I am sweating a lot and in those conditions I suffer a bit. I was able to play aggressive in the fourth. He is an amazing player and has a great future.”
There were several upsets in the women’s draw, where Serbian seventh seed Ana Ivanovic was beaten 6-3 3-6 6-3 by Dominika Cibulkova of Slovakia, and she was followed out of the tournament by five more seeds