Kyle Edmund failed to clear the opening round of the Rogers Cup in Toronto after suffering a bruising 6-1 6-2 loss to Diego Schwartzman.
After rain delayed play, the British number one was dismissed in an hour by the Argentine number 11 seed on Monday evening.
Edmund appeared outgunned by Schwartzman from the off, losing his first service game as the world number 12 notched up three.
The Briton, ranked 16th by the ATP, made it on to the scoreboard in the fourth game, but he was broken again in the sixth and went on to lose the set.
Edmund, who after a bye was knocked out of the Citi Open's second round by Sir Andy Murray a week ago, appeared to have regained some composure as play resumed.
However, with the score 2-2, the match ran away from him in the fifth game, Schwartzman breaking his serve.
Edmund managed to save one break point in the seventh, but he was overcome by his opponent who took the match in the eighth.