Roger Federer defeated by John Millman after struggling with US Open heat, Maria Sharapova knocked out too
Defeat means there will not be a Federer v Djokovic quarter-final clash at Flushing Meadows
There will be no epic quarter-final showdown between Roger Federer and Novak Djokovic at the US Open after the Swiss suffered a surprise four-set defeat to John Millman at Flushing Meadows.
Australian Millman, who had never previously beaten a top ten opponent, was not given much hope pre-match but defeated the 20-time grand slam winner 3-6 7-5 7-6 (8/6) 7-6 (7/3).
Federer produced one of his poorest games on the big stage against the world No.55, struggling with all parts of his game and making 76 unforced errors.
The match did not finish until nearly 1am but the temperature was still around 30C with extremely high humidity.
Earlier, Djokovic also struggled with the heat for the second time this tournament but came through a 6-3 6-4 6-3 victory over Joao Sousa relatively comfortably.
The other quarter-final in the bottom half of the draw will be a rematch of the 2014 final between Marin Cilic and Kei Nishikori.
Nishikori defeated Philipp Kohlschreiber 6-3 6-2 7-5 while Cilic was a 7-6 (8/6) 6-2 6-4 winner against David Goffin.
In the women's draw, there was another shock as Maria Sharapova's long-unbeaten record in night session matches at Flushing Meadows was ended in the fourth round by Carla Suarez Navarro.
Sharapova, the champion in 2006, had won 23 straight matches under the lights, including her previous three contests this year, but Suarez Navarro, on her 30th birthday, clinched a 6-4 6-3 victory to reach her second quarter-final in New York.
It was well deserved for the Spanish 30th seed, who next plays Madison Keys, as she drew the errors from the Sharapova racket - 38 unforced, including eight double faults - and used her flowing single-handed backhand to great effect.
Naomi Osaka reached her first grand slam quarter-final with victory over fellow 20-year-old Aryna Sabalenka.
In one of the most highly-anticipated women's matches of the tournament, between two players who are expected to face each other many more times on the big stage, it was Japanese-American Osaka who prevailed 6-3 2-6 6-4.
Osaka next faces Ukraine's Lesia Tsurenko, who struggled badly with the heat on the open Grandstand court against Marketa Vondrousova but battled from a set down to win 6-7 (3/7) 7-5 6-2.
Keys, the runner-up last year, is the highest seed left in the bottom half of the draw at 14 and breezed through to the last eight again with a 6-1 6-3 victory over Dominika Cibulkova.
