Canada coach Jesse Marsch said he wants his side to be fearless when they take on Lionel Messi's Argentina in their Copa America opener on Thursday.

The former RB Leipzig and Leeds United coach acknowledged, however, that Canada may struggle to limit the impact of eight-time Ballon d'Or winner Messi, who is expected to start for World Cup champions Argentina as they look to defend their continental crown.

"An organised and disciplined team will be important. We've talked a lot about that, and then an aggressive team that plays fearless, a team that goes after the game," March told a news conference on Wednesday.

"The challenge with Messi is not just his quality but his ability to kind of move around in the game. He doesn't just show up in the same places all the time.

"He's very clever about coming underneath at times, about how he moves off the back line. Obviously, anytime he gets on the ball, the way that he can start to create combinations and really provide confidence and poise and quality for the team is very unique, right? This is what makes him the best player to ever play the game."

The 50-year-old American coach, who took over last month following John Herdman's departure in August, had only two friendlies to prepare for the tournament, a 4-0 defeat by the Netherlands and a 0-0 draw with France.

"I've played against him (Messi), coached against him a few times and had some successes, but he always finds ways to make a difference because his quality is so amazing. So that'll be the challenge for us," Marsch added.

"The key I think is to really be always aware of where he is and make sure that he's not in open space and that we're able to close space and try to make it difficult for him."

Canada will also face Peru and Chile in Group A.

The tournament brings together 10 South American teams and six from North and Central America and the Caribbean in the second Copa hosted by the United States.