Five-time champion Roger Federer and 2012 winner Andy Murray reached the US Open second round Tuesday as the crushing heat took the number of first-round retirements to a record 10. Second-seeded Federer had little trouble in seeing off Argentina's world number 34 Leonardo Mayer 6-1, 6-2, 6-2 in just 77 minutes on Arthur Ashe Stadium. The 34-year-old Swiss, bidding to become the oldest champion in New York in 45 years, fired 12 aces, 29 winners and broke serve six times. The 17-time Grand Slam champion goes on to face Belgium's Steve Darcis, who was handed a place in the next stage when Cypriot veteran Marcos Baghdatis retired injured with a groin strain. It was the 10th retirement in the men's event in the first round; there have also been two pullouts in the women's draw. Third seed Murray downed the sport's latest bogeyman, Nick Kyrgios, 7-5, 6-3, 4-6, 6-1 for his fourth win in four meetings against the Australian and third in three Grand Slam matchups this year. In the women's draw, Lucie Safarova joined the seeds casualty list when the Czech left-hander became the fourth top-10 player to lose in the first round.