Stefanos Tsitsipas’ best-ever run at an ATP Tour Masters event has continued after he rallied to upset third-ranked Alexander Zverev 3-6 7-6 (13-11) 6-4 and advance to the semi-finals of the Rogers Cup in Toronto.

The 19-year-old Greek rising star trailed by a set and a break, but he got back on serve late in the second set and then saved two match points in a marathon tiebreaker before forcing the decider.

The 21-year-old German slammed his racquet to the ground in frustration after missing a cross-court backhand to lose the second set.

Tsitsipas struggled on serve in the final set, but he managed to save eight of the nine break points he faced and broke Zverev’s serve on two occasions to wrap up the victory in two hours and 27 minutes.

For Tsitsipas, who had defeated Austrian world No. 8 Dominic Thiem and 10th-ranked Serbian Novak Djokovic in the two previous rounds, it was his third straight victory over a top 10 opponent.

Before this week, he had never advanced past the second round of one of the nine Masters events, which are among the biggest tournaments outside of tennis’ four grand slams.

His opponent in Saturday’s semi-finals will be South African Wimbledon runner-up Kevin Anderson, the world No. 6, who brushed aside Bulgaria’s Grigor Dimitrov 6-2 6-2 on Friday.

The other two men’s singles quarter-finals will be played on Friday night and pit the Netherlands’ Robin Haase against Russia’s Karen Khachanov and Spanish world No. 1 Rafael Nadal against Croatian world No. 7 Marin Cilic.