Greek tyro Stefanos Tsitsipas' dream run at the Rogers Cup continued on Friday as the teenager toppled defending champion Alexander Zverev 3-6 7-6(11) 6-4 to reach the semi-finals in Toronto.
The win over world number three Zverev looked unlikely when the 19-year-old dropped the first set and fell behind 2-5 in the second.
But Tsitsipas managed to save two match points and shifted the momentum after edging Zverev in a marathon second-set tiebreak.
Extending the match paid off for Tsitsipas as Zverev made a number of uncharacteristic errors in a tight third set and he handed the world number 27 victory with a double fault on match point.
The win was the Greek's third straight over a top 10 opponent after he dispatched Dominic Thiem and Novak Djokovic in the previous two rounds.
"I'm confused now, is this real?" Tsitsipas said. "This shows that with dedication and work, dreams do come true."
Zverev, 21, was accused of poor sportsmanship after he failed to congratulate his opponent when speaking to reporters after the match.
"I don't think he played that well. I think the match was absolutely pathetic on all levels," the German said.
"I'm very honest with you guys. Today was an absolute pathetic match I don't even think he played well."
Next up for Tsitsipas is a showdown with big-serving South African Kevin Anderson, who thrashed Bulgarian Grigor Dimitrov 6-2 6-2 earlier on Friday.
Fourth seed Anderson, runner-up at Wimbledon last month, was never broken and won 81 percent of his first serves. [Reuters]