Nick Kyrgios advanced to the third round at the Miami Open on a day where multiple grand slam champions Stan Wawrinka and Rafael Nadal fell by the wayside.
Kyrgios made short work of Cypriot Marcos Baghdatis, defeating the one-time Australian Open finalist 6-2 6-1 in just under an hour, the Aussie firing down 14 aces in the impressive victory.
Kyrgios was seeded to face big-serving American John Isner but the world No.13 became yet another surprise casualty, going down to countryman and world No.132 Tim Smyczek 6-2 2-6 7-6 (7-5).
Kyrgios' quarter of the draw is now wide open and, if he beats Smyczek, he is certain to face a player ranked below him for a spot in the quarter-finals.
While Kyrgios made it through, there was no such luck for fellow Australian John Millman, who fell 7-5 6-4 in his second-round match to Uruguayan 23rd seed Pablo Cuevas.
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On a mixed day for the Aussies, it was a shocker for two of tennis' biggest names, Wawrinka humbled and Nadal unwell in the Florida heat.
Nadal faded and retired after falling behind in the third set of his match against Bosnian Damir Dzumhur.
The fifth seed trailed 2-6 6-4 3-0 when he called it quits after losing a point to fall behind 30-15.
He had earlier consulted with a trainer at his chair between games three times, and had his blood pressure checked.
The match lasted less than two hours, but the weather was sunny and humid, with a temperature approaching 90 degrees and even higher on the stadium hardcourt.
Nadal said he started feeling ill at the end of the first set.
"It was getting worse and worse and worse," Nadal said.
"I get a little bit scared - too dizzy. I felt I was not safe, so I decided to go. I wanted to finish the match, but I seriously couldn't."
The 14-time grand slam champion hasn't won a tournament since August, but it had been 443 matches since he retired - in the 2010 Australian Open quarter-finals against Andy Murray.
The heat also appeared to bother Dzumhur, who consulted with a trainer following the first set.
Nadal's departure left the draw without three of the five highest-seeded men.
Wawrinka earlier suffered a shock 6-4 6-3 loss to world No.51 Russian Andrey Kuznetsov and world No.3 Roger Federer withdrew on Friday because of a stomach virus.
Kei Nishikori defeated qualifier Pierre-Hughes Herbert 6-2 7-6 (7-4) while Milos Raonic, the runner-up at Indian Wells, beat Denis Kudla 7-6 (7-4) 6-4 to also advance and he will play Jack Sock in the third round.
In-form Frenchman Gael Monfils is also through to the third round after a comfortable 6-3 6-2 win over Japanese qualifier Tatsuma Ito.
Second seed Murray progressed 6-3 7-5 over Denis Istomin in the night match and will play Bulgarian Grigor Dimitrov in the third round.
Dimitrov earlier squeaked past Argentine Federico Delbonis 7-6 (10-8) 4-6 6-4.
