After a lacklustre display against Ecuador in the quarter-finals, Messi looked back to himself again, connecting with Angel Di Maria and strike partner Julian Alvarez, who also scored.
"I'm living it like I lived it in the last Copa America, in the last World Cup....these are the last battles and I'm enjoying them to the maximum," he told TyC Sports after the win set up a meeting with Uruguay or Colombia in the final.
Messi, now playing with Inter Miami in Major League Soccer, has yet to indicate whether he will continue to play with Argentina in the 2026 World Cup, which will feature a final at the New Jersey venue.
But asked about Messi's "last battles" comment, Argentina coach Lionel Scaloni asked for calm.
"We have to leave him alone, he knows that we will not be the ones to close the door on him. He can stay with us as long as he wants, even when he retires...Let him decide what he wants," he said.
Messi has chance to win a third straight major title with his national side following their 2022 World Cup triumph and their 2021 Copa America win.
The eight-time Ballon d'Or winner referenced veteran team-mates Di Maria and Nicolas Otamendi and said that the success was validation for the difficult barren years the team had suffered.
"The truth is that it's crazy what this group has done, what the Argentina national team has been doing, because after all this it gives value to all (the tournaments) I and the old generation have played in," Messi said on TyC Sports.
"It's not easy for us to be in a final again, for us to compete again to be champions," he added after the victory at MetLife Stadium.
Despite Argentina reaching the final with some comfort against Canada, the former Barcelona forward said it had been a tough test so far.
"It's a difficult Copa, evenly matched, with very bad pitches, with high temperatures, very tough teams, and for us to be in a final again is something to enjoy," he said.
Goalkeeper Emiliano Martinez said that despite being world champions the joy of reaching a final was just as intense as ever.
"It's a source of pride as an Argentine, as a representative of this national team, to be able to play in another final. It feels as if it was the first time," he said.