• Australian stuns world No 2 with 6-4, 6-4, 2-6, 6-4 win
• Serbian made to wait in attempt to claim 25th slam title.

Alexei Popyrin entered the US Open in the best form of his career and with a tailwind of confidence after picking off a parade of higher-ranked players to win the Montreal Masters earlier this month. On Friday night, the 25-year-old Sydneysider’s charmed summer reached new heights with a seismic upset of Novak Djokovic that propelled him into the second week of a major tournament for the first time in 23 appearances.

Popyrin, the No 28 seed, ran out to a two-set lead before holding on to win 6-4, 6-4, 2-6, 6-4 before a stunned crowd inside Arthur Ashe Stadium, denying the second-seeded Djokovic in his bid for a record 25th grand slam singles title and a rare US Open repeat. He advances to the fourth round in a suddenly wide-open quarter where he will meet Frances Tiafoe, the 20th seed who came through a 4-6, 7-5, 6-7 (5), 6-4, 6-3 thriller against fellow American Ben Shelton during the day session.

Just an awful match for me,” said Djokovic, whose 13 double faults on Friday were a career-high for a tour-level match. “Tournaments like this happen.