Third-seeded Milos Raonic of Thornhill, Ont., was knocked out 6-4, 6-4 by wild-card entry Peter Gojowczyk in the second round of the Gerry Weber Open in Halle, Germany, on Wednesday.
Gojowczyk, the world No. 120 from Germany, saved both break points he faced and won in one hour, 12 minutes to book a quarter-final with Colombia's Alejandro Falla, who beat Dutchman Robin Haase 7-6 (1), 6-4.
Former champion Philipp Kohlschreiber advanced to the quarter-finals with a 6-2, 6-4 win over French qualifier Pierre-Hugues Herbert.
Kohlschreiber, who won the grass-court tournament in 2011, will next play Rafael Nadal or German compatriot Dustin Brown.
Fourth-seeded Kei Nishikori booked his quarter-final place by beating Gael Monfils 6-1, 3-6, 6-3.