Poland defeated Canada 2-1 at the Hopman Cup on Sunday, leaving Milos Raonic and Eugenie Bouchard with a 1-1 group record at the eight-nation mixed team event.
Grzegroz Panfil, a substitute for injured Wimbledon semifinalist Jerzy Janowicz, stunned the 11th-ranked Raonic 7-6 (1), 6-3 in the biggest upset of the day. Panfil holds the No. 288 position in the world rankings.
In the women's match, fifth-ranked Agnieszka Radwanska outlasted Bouchard 6-3, 6-7 (7), 6-2. The 19-year-old Canadian is ranked 32nd in the world.
Raonic and Bouchard later teamed up for a 6-3, 5-7, 10-3 mixed doubles win over Radwanska and Panfil. The Czech Republic swept defending champion Spain 3-0 in the other tie Sunday.
The Canadians opened the tournament with a win over Australia and will close out the round robin Thursday with a match against Italy.
Panfil, 25, lost his only career match at the ATP level back in 2006. Raonic, from Thornhill, Ont., came out firing but was overwhelmed by the inspired underdog in 81 minutes.
"I was sloppy at the start and then he closed out the match incredibly [well," Raonic said.
Raonic named male athlete of the year
The 23-year-old Canadian won the Lionel Conacher Award earlier in the week as The Canadian Press male athlete of the year. Raonic is also gearing up for the Australian Open, which begins in two weeks time.
"The time to be playing my best tennis is after January 13," he said. "Of course I hate to lose, I want to win these kind of matches. But it's not the end of the world.
"This is also a training week for us and I'm pleased to have three days now to work on things."
Bouchard put in a solid effort against the more experienced Radwanska in a match that lasted two and a half hours.
"I felt like I didn't play well in the first set, I lost a few games in a row," Bouchard said. "But I was happy to at least turn it around and make it a match.
"I was a bit tired at end and she kept her level up all the way. It was encouraging that I was able to raise my game, but I need to keep that level more consistently."
Bouchard saved three match points in the second-set tiebreaker before converting on her first set point to pull even.
"I was trying to stay with her in the second set, but she's a tricky player and gets a lot of balls back," she said. "I missed a few of my finish shots. It's always disappointing to lose, I need to do some more work and get more consistency into my game.
"But I did serve well and put pressure on her. I just hit a few too many mistakes."
Bouchard won the Bobbie Rosenfeld Award earlier this week as The Canadian Press female athlete of the year.