Scaloni reflects on 'very sad' violence before Brazil vs. Argentina (0:42)Lionel Scaloni reacts to clashes between the police and fans before Argentina's game against Brazil. (0:42)
Messi, 36, who recently completed his first season with MLS side Inter Miami CF, has not given an indication as to when he will retire from football.
"We tell him [Messi] to play for as long as he can," Scaloni told Christian Vieri in a Twitch interview.
"He has proved that he doesn't have an end. You don't know when he will give [it] up. It's incredible."
According to Scaloni, the football field is a refuge for the player.
"He is happy on a football pitch," he said. "Off it, I think it's hard to be Leo because he goes out of his home and he is surrounded by many people. On the pitch, where the ball is, he is happy."
Messi and Scaloni won the World Cup in 2022. Photo by Marcelo Endelli/Getty Images
At least for Messi, he has the triumph that had been missing in his career after winning the 2022 World Cup.
Messi was voted the player of the tournament in Qatar after scoring seven goals and setting up three more in seven appearances as Argentina won their first world title in 36 years.
"Everyone says the World Cup is the most extraordinary thing for a player," Scaloni said. "He was missing [winning] a World Cup.
"I believe as good as he is, he also played [in Qatar] with his heart. And then he becomes unstoppable."
Scaloni still marvels at Messi's talent, even after coaching him since 2018.
"To watch him up close, it is something very difficult to describe," Scaloni said. "You have to see him. If I told you the things he does in training, you wouldn't believe me. It's crazy."
Messi has expressed a desire to continue playing for Argentina but unlike teammate Ángel Di María, who announced he will retire after the 2024 Copa America, the former Barcelona star hasn't made a decision.
"I think he can continue play [for the national team] but the decision is his," Scaloni said of Messi. "He can play wherever he wants and the team arranges itself around him. "
"I don't know if I have a lot or a little left, but after the career I've had, the only thing I have left is to continue enjoying it," Messi said.
"As long as I am physically well, I will continue competing, hopefully it will be a long time."