Sixth seed Alexander Zverev has outlasted Frances Tiafoe in the US Open second round, enhancing his reputation as one of the sport's best young players.
Zverev, who suffered a shock first-round defeat at the All-England Tennis Club last month, showed off his trademark endurance under the blistering sun by saving eight of the 11 break points Tiafoe created on the German's serve.
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Zverev, who fired down 22 aces, appeared exhausted after a match lasting more than three hours, winning 6-3 3-6 6-2 2-6 6-3.
"I've been here before," he said afterwards.
"It's usually what I do in the first few rounds of a grand slam, play five sets.
"Maybe it's to entertain the crowd.
"Frances gave me a real fight. I'm just happy to get the win somehow. I know if it goes the distance I am ready.
"I've known Frances since we were little kids, we played each other all through juniors.
"Every match we play is getting tougher and tougher, hopefully, that will continue and we will play bigger matches throughout our careers."
In the other men's matches on Thursday, Australian Alex de Minaur thrashed Chilean Cristian Garin 6-3 7-5 6-3.
Belgian David Goffin beat French qualifier Gregoire Barrere 6-2 6-2 6-2, while American Denis Kudla defeated Serb Dusan Lajovic 7-5 7-5 0-6 6-3.
Swiss ace Stan Wawrinka beat Frenchman Jeremy Chardy 6-4 6-3 6-7 (3-7) 6-3 and Briton Dan Evans won 6-4 6-3 6-7 (4-7) 6-4 to send Lucas Pouille packing.
Spain's Pablo Carreno-Busta also beat Lithuanian Ricardas Berankis 6-4 6-7 (3-7) 6-2 6-0.
Reuters