(Reuters) – Unseeded American teenager Frances Tiafoe upset red-hot Alexander Zverev 4-6 6-3 6-4 to reach the third round of the Cincinnati Open on Wednesday.
World number seven Zverev, who stunned Roger Federer in the Montreal final last week after claiming the title in Washington D.C., was on a 10-match winning streak but faded in the final set against the energetic baseliner.
It was 19-year-old Tiafoe’s first win over a top-10 player and he bounded around the court in joy, thumping his chest to a standing ovation after Zverev floated a backhand long on match point with his third unforced error of the last game.
“I saw he was a bit tired, but he was still competing. It was tough. I was happy to get through it,” 87th-ranked Tiafoe told Tennis Channel. “My game plan was to keep the rallies long and keep him out there and that’s what I did.”
Earlier, Bulgarian seventh seed Grigor Dimitrov beat Feliciano Lopez 7-6(5) 6-4 to set up a last-16 clash with Juan Martin Del Potro.
The 28-year-old Del Potro, playing at Cincinnati for the first time in four years after reaching the semi-finals in 2012 and 2013, advanced with a 6-4 6-4 win over American qualifier Mitchell Krueger, winning each set on a late break.
Dimitrov has not beaten Del Potro in five career meetings, with the most recent defeat coming at Rome in May.