Andy Murray crashed out of the ATP Rogers Cup in Montreal on Thursday, suffering a straight-sets defeat at the hands of Latvia's Ernests Gulbis.
The world number two was beaten 6-4 6-3 in his first tournament since winning Wimbledon.
Gulbis admitted he had managed to beat the British second seed despite not playing his best tennis.
"The thing that pleased me the most was that I won," the 24-year-old told Sky Sports 3.
"I struggled in the first set from the baseline but got more confident and took my chances.
"I didn't blink when serving out for the match but I didn't play my best tennis."
Gulbis will face Milos Raonic in the quarter-finals after the Canadian 11th seed saw off sixth seed Juan Martin Del Potro of Argentina 7-5 6-4.
In contrast to Murray, fourth seed Rafael Nadal continued his smooth progress by ousting big-serving Pole Jerzy Janowicz 7-6 (8/6) 6-4.
"I was able to play without limitations these two matches; hopefully I can continue like this," the Spaniard said in his on-court interview. "That's my goal. I will try to forget this injury with my knee."