STUTTGART, Germany (AP) -- German qualifier Dustin Brown upset top-seeded Alexander Zverev 6-4, 6-7 (3), 6-3 Thursday to reach the quarterfinals of the Stuttgart Open.
Brown was playing just his second tour-level match of the year but hit a number of spectacular winners to beat the fifth-ranked Zverev and record his first win against a top-10 opponent since 2017.
Matteo Berrettini caused another upset earlier Thursday, defeating second-seeded Karen Khachanov 6-4, 6-2.
The Stuttgart Open made the switch from clay to grass in 2015.
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