Wales say Canada's negative play at the breakdown upset their pattern in the tourists' 23-32 win in Toronto.
"The feeling is frustration on the whole," said caretaker coach Robin McBryde after his first game in charge.
"Fair play to Canada, they made it difficult for us, especially at the breakdown. We were unable to build up a head of steam or get any quick ball."
Canada forwards coach John Tait said: "The penalty count went against us at times, I'm sure Wales infringed."
The victory for an inexperienced Wales side - shorn of their Lions stars and players from the Dragons - was their first match of a two-Test summer tour than concludes against the USA in Chicago next Saturday.
Jones proud of Wales youngsters
Captain Ryan Jones was critical of the tactics employed by Canada.
"It was pretty tough and physical, but we didn't expect anything else from them after the way they performed against us at the Millennium Stadium last autumn," he told BBC Sport Wales.
"The breakdown and the set-piece were contentious.
"But I always enjoy playing for Wales and I enjoyed playing back at number eight - I was a bit rusty, but it was good to get my hands on the ball.
"It's been a fantastic tour so far. The boys have been great and the youngsters have come in and done us proud."
McBryde also said he was pleased with the youngsters, but insists that he expects improvement next week.
"We're disappointed with the level of accuracy and the number of opportunities we failed to convert, we need to address that," said McBryde, in charge while Warren Gatland, Shaun Edwards and Rob Howley are on Lions coaching duty.
"On a positive note, we got the win and blooded a few youngsters who have come through well."
McBryde said that there could be changes in the team for next week, winger Mark Jones being monitored after injury ruled him out of the Canada game while Gareth Cooper limped off at half-time in Toronto.
"We don't give caps away lightly, you have to earn the right to wear the shirt," McBryde told BBC Sport Wales.
"We'll assess a few of the injuries and base selection on performance."
Meanwhile, Tait was pleased with Canada's improved performance from last week's 25-6 loss to Ireland in Vancouver.
"The result wasn't right, but we kept playing for the full 80 minutes, that's an improvement on last week," Tait told BBC Sport Wales.
"The guys are disappointed because they had a good start to the second half but then there was a 20-minute period where we made a few mistakes, the calls went against us and we couldn't get out of our 22.
"But we played some nice rugby and scored two attractive tries."
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