Frances Tiafoe has advanced to the fourth round at Melbourne Park, his first appearance in the round of 16 at any Grand Slam.
The 20-year-old American beat 34-year-old Andreas Seppi 6-7 (3), 6-3, 4-6, 6-4, 6-3 on Court 3, where matches began 2 1-2 hours late because of morning rain.
The No. 39-ranked Tiafoe beat fifth-seeded Kevin Anderson in four sets in the second round, and followed it up with a biceps-slapping celebration that drew plenty of attention.
He will next play 20th-seeded Grigor Dimitrov, who beat Thomas Fabbiano 7-6 (5), 6-4, 6-4.