The third-seeded Briton Andy Murray put on a composed display to overcome the mercurial Austrailan Nick Kyrgios in four sets in their second round US Open match in New York.
The 20-year-old Kyrgios showed off his powerful serve and groundstrokes but the 37th-ranked Australian frequently substituted efficiency for showmanship and failed to take advantage of his numerous opportunities.
Murray, the 2012 U.S. Open champion and 2013 Wimbledon winner, played straight man to the flippant Australian, who unnecessarily tried 'tweener' shots through his legs and jumped extravagantly on routine forehands that he buried into the net as Murray won 7-5 6-3 4-6 6-1.
The Australian, playing under an ATP Tour probation for crude personal comments made to Stan Wawrinka during a match in Montreal last month, should have made the contest much closer but could only convert three of 14 break point opportunities.
The Scotsman had beaten Kyrgios in straight sets in their three previous meetings, eliminating him this year from two other grand slams, in the Australian quarter-finals and third round of the French Open.
Meanwhile Roger Federer glided to another victory.
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.
In another wrenching defeat for France, Paul-Henri Mathieu fell to Japan's Yoshihito Nishioka in five sets.
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 Center 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 favored 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.