Felix Auger-Aliassime hit out at his own poor performance after his 7-5 6-3 6-3 loss to world No. 52 Yoshihito Nishioka.
Auger-Aliassime was a firm pre-match favourite but the Japanese underdog won in straight sets.
“He played good. Also, I wasn’t good, and I could have been better on many of those opportunities,” Auger-Aliassime said.
“I give him credit and I take responsibility for that because I just felt like there were too many times where I just didn’t step up and played a decent point.”
Auger-Aliassime said his issue wasn’t technical. “The issue could have been mentally, tactically,” he said.
“You always see what you could do better but when you’re in the moment you try your best. You try to win, but sometimes it’s not enough, you’re not good enough on the day.
“Now it’s past me and I’ve got to accept that.”