NEW YORK (Reuters) - Roger Federer glided to victory on another hot, steamy day at the U.S. Open, the envy of a clutch of men's players made to work overtime on Tuesday at the season's final grand slam.
Federer, who has been in sizzling form since reaching the Wimbledon finals, dashed past 34th-ranked Leonardo Mayer of Argentina 6-1 6-2 6-2 to launch his campaign for a sixth U.S. Open crown and first slam title since the 2012 Wimbledon.
"I got off to a good start and he was a bit shaky. I was very happy," said Federer. "My serve got better and better as the match went on. Conditions are fast, so I was trying to play fast-court tennis and it worked very well today."
The 34-year-old Swiss, looking cool in the 90-plus degree heat after his light, first-round exertions, next faces either Marcos Baghdatis of Cyprus or Belgian Steve Darcis.
Others were sorely tested.
Three players in the bottom half of the men's draw had to go the distance in the severe heat at Flushing Meadows, including French 11th seed Gilles Simon, who looked to have iced victory after taking a 6-2 6-4 3-0 lead over American Donald Young.
But the Frenchman stumbled, and the 26-year-old American, once hailed as the next great U.S. player, saw an opportunity and turned the match upside down for a 2-6 4-6 6-4 6-4 6-4 win.
"I really had it on my racquet," said Simon. "I was not able to do anything on the tennis court. I think Donald realized it and then played what he had to play to take me down in five sets. It's a terrible result for me today."
In another wrenching defeat for France, Paul-Henri Mathieu fell to Japan's Yoshihito Nishioka in five sets.
The 128th-ranked Yoshihito Nishioka, who saw fourth-seeded compatriot and 2014 finalist Kei Nishikoria drummed out in five sets on Monday, booked himself into the second round with a 6-4 2-6 6-7(7) 6-1 6-2 victory.
Dutchman Robin Haase also made a Houdini-like escape against Germany's Dustin Brown to register a 4-6 4-6 6-3 7-5 6-4 victory.
Heat may have been a factor in claiming other hard-luck victims at the U.S. National Tennis Centre as four players retired from their matches.
Australian Lleyton Hewitt, the 2001 U.S. Open winner, advanced 6-0 7-6(2) 1-0 when Aleksandr Nedovyseov of Kazakhstan retired.
Misfortune favoured the French and went the other way for the Aussies when 12th seed Richard Gasquet advanced 4-6 6-1 4-6 6-3 2-0 when Thanasi Kokkinakis retired.
Women's second seed Simona Halep also had an abbreviated match as she advanced 6-2 3-0 after New Zealand's Marina Erakovic retired with a knee injury.
The in-form Halep, who reached the finals at U.S. Open tune-up events in Toronto and Cincinnati, barely broke a sweat on Arthur Ashe Stadium court, needing a mere 47 minutes to see off the 99th-ranked New Zealander.
Also sprinting to victory was fourth seed Carolina Wozniacki, who dismissed U.S. national college champion Jamie Loeb 6-2 6-0.
The women's draw continued to produce upsets for a second consecutive day as Czech sixth seed and French Open finalist Lucie Safarova fell 6-4 6-1 to Ukrainian Lesia Tsurenko.
Fourteenth seed Timea Bacsinszky of Switzerland was also shown the door, ushered out by 42nd-ranked Czech Barbora Strycova 7-5 6-0.
They joined Monday's first-round casualties that included Serbian seventh seed Ana Ivanovic, eighth seeded Czech Karolina Pliskova and 10th-seed Carla Suarez Navarro of Spain.
"I wasn't surprised (by the upsets), it is normal," said 23-year-old Halep. "Everyone is fighting like crazy because it's the last grand slam (of the year)."
Editing by Frank Pingue