FLUSHING MEADOWS, N.Y., Aug. 31 (UPI) -- At the start of Day One at the United States Open Tennis Championships Monday, there were 32 seeded women in the tournament's draw. A few hours later, six were already gone.
Welcome to America's Grand Slam.
The 2015 edition of the prestigious tournament started Monday with several high-profile players in action -- from defending women's champion Serena Williams to five-time finalist and 2011 winner Novak Djokovic.
In U.S. Open history, it is typically the men's draw that is rife with upsets so early in the tournament -- yet Monday, only one seeded men's player was bounced: 2014 runner-up Kei Nishikori.
The Japanese ace, ranked No. 4 in this year's tournament, was defeated in his first round match by Frenchman Benoit Paire.
"It's very sad to lose always first round," he said. "I don't think I played bad. Didn't play great, but still, it's never easy first match.
"I hope I can come back strong next year."
"Maybe he was a little bit nervous," Paire said, noting that perhaps the pressure of being a finalist last year got to Nishikori. "But to be honest, I think I'm lucky."
Stephens was eliminated in the opening round by another rising American women's star, Coco Vandeweghe. Defending champion Serena Williams played the women's night match Monday, just a few hours after her sister Venus won her opening round match.
American Mardy Fish, who will retire at the conclusion of the U.S. Open, needed four sets to advance to the second round -- but he got the victory.
"I realize this is my last event, but I've got so many different sort of emotions going through that don't have anything to do with that," Fish said. "I want to sort of take in everything and enjoy all aspects of this tournament, because it is so great."
Former champion Rafael Nadal, seeded eighth, will play Croatia's Borna Coric in the men's night match. No. 2 seed and former champion Roger Federer will play his opening round match Tuesday morning. No. 3 Andy Murray is scheduled for Tuesday's night session.
-Djokovic, the world No. 1, cruised to a first round victory against Brazil's Joao Souza (6-1, 6-1, 6-1).
-Defending men's champion Marin Cilic, seeded ninth, won in straight sets Monday.
-American Madison Keys defeated Czech Klara Koukalova in straight sets to advance to round two.