Lionel Messi continues to amaze Canada head coach Jesse Marsch after inspiring Argentina to victory in the opening game of the Copa America.

World champions Argentina triumphed 2-0 over Canada in Atlanta, making an impressive start to their title defence in the tournament.

Messi had a hand in both goals as Julian Alvarez and Lautaro Martinez struck in the second half on Thursday.

The Martinez goal saw Messi rack up his 17th Copa America assist. Since 2011, he has registered over three times as many goals created as any other player in the competition, with Angel Di Maria and Alexis Sanchez ranking second on five each.

Messi turns 37 on Monday, and has a stunning 20-year professional career under his belt, but that does not mean he does not continue to stun and surprise his opponents, including Marsch.

Marsch felt his team did what they could to remain compact, but Messi, who created a game-leading five chances, proved the difference on his record-breaking 35th Copa appearance.

The Canada boss explained the task of having to face Messi was amazing and awful in equal measure, with the forward having a massive impact even though the coach felt his gameplan to try and limit the Argentina star had been implemented reasonably well.

"Yeah, with Messi we talked a lot about our compactness and then identifying the spaces that he likes to show up in," Marsch said after the game.

"We talked about not diving in because it's hard to win tackles from him.

"What happens is if you eliminate yourself or if you start diving in for tackles, he's really good slipping and moving and getting back again and making little final plays.

"This is what I say about Messi: I have coached against him several times and I feel like we have had a good match plan and we have executed a lot of good things.

"But he is so good, he is that good that he still makes plays. The two balls he makes on the two goals I think are world class. 

"Amazing, it's awful. It's amazing."

Inter Miami star Messi had a game-leading six shots, getting three of them on target, and also led the match for touches in the opponent's box (nine) in an all-action display.

Despite the challenge of facing Messi, Canada captain Alphonso Davies felt his side should have done more to follow up on a battling first-half performance that meant the game goalless at half-time.

"We have to change our attitude towards the game," Davies said to TSN.

"The first half we played well, but in the second half we let every long ball bounce. 

"It was a disappointing result, we need to look at everything we did wrong in the game and fix it as soon as possible."

Argentina return to action against Chile on Tuesday, which is also when Canada will hope to pick up their first points of the campaign against Peru.