Kyle Edmund lost to an injured Vasek Pospisil as Great Britain and Canada ended day one of their Davis Cup World Group tie level at 1-1 in Ottawa.
Briton Dan Evans beat 17-year-old Denis Shapovalov 6-3 6-3 6-4 before Pospisil upset Edmund 6-4 6-1 7-6 (7-3).
Pospisil, ranked 86 places below Edmund at 133rd in the world, overcame a leg injury to level the best-of-five tie.
Jamie Murray and Dom Inglot are scheduled to face Daniel Nestor and Pospisil in Saturday’s doubles contest.
The two nations are missing their leading players as world number one Andy Murray recuperates following the Australian Open, while Canada’s world number four Milos Raonic is injured.
“We had a video from Andy last night and [captain] Leon [Smith] put it on the big screen,” Evans said.
“I’m guessing he was watching. He said he would be. It’s obviously nice he supports the team. He’s a good guy to have in our corner.”
Evans successfully carried the responsibility of being Britain’s number one as he converted a gulf in experience over world number 234 Shapovalov into a straight-sets victory – the Briton’s first win in a live Davis Cup rubber since 2013.
Shapovalov gave evidence that he has a bright future, the Wimbledon junior champion hitting plenty of flashing winners behind a swinging left-handed serve, but 39 unforced errors proved too much.
The Canadian dropped serve in a nervous opening game and again to lose the set, but he threatened more in the second and it took an ace and a deft drop volley for Evans to see off the first two break points against him.
That was as close as Shapovalov would get, however, with Evans then breaking thanks to a fantastic lob and making the decisive move at 4-3 in the third set.
“I tried to get on top early,” Evans said. “That was the plan, to come out and silence him and not give him confidence. I did that and then rolled him from then on. I was happy with way I played.”
Pospisil too strong for Edmund
Edmund, ranked 47th in the world, looked a good bet to increase Britain’s lead against Pospisil, who has slipped from 25th three years ago to a lowly 133rd in the world.
The Canadian, 26, was further hampered by a left leg injury which required a medical timeout as early as the fifth game, and continued to require bouts of treatment.
It was therefore all the more remarkable that Pospisil reeled off eight of nine games following the timeout with some fine serving, while Edmund produced an error-strewn performance across the net.
The fast pace of the court allowed Pospisil to keep the points short, race through his serving games and put pressure on the increasingly vulnerable Edmund serve.
Edmund, 22, managed to get through to a tie-break in the third set but was outplayed once again, ending with eight double faults and 39 unforced errors.
“It was just not good enough, pretty dismal from my standards,” the Briton said.
“Everyone can accept winning and losing but it needs to be a lot better at this level. I’m just very disappointed for myself, for the team.
“It’s annoying when you have support like that and fans come out and spend money and travel and to put on a performance like that. You just really want to do well.”
Captain Smith added: “The most important thing is to dust it [Edmund’s defeat] off but focus now on the next matches. There’s a lot of tennis to be played