Gerardo Martino hailed the impact of Lionel Messi after the Argentina captain inspired the side to a 5-0 win over Panama in the Copa America Centenario.
Messi came off the bench with under 30 minutes left to play on Friday and scored a hat-trick as Argentina eased into the quarter-finals of the tournament.
The Barcelona star was named among the substitutes after recovering from a back injury, and was given half an hour as Argentina toiled to close out the game.
Nicolas Otamendi had opened the scoring early on and it took Messi just seven minutes to contribute after coming on, before adding two more goals and having a hand in Argentina's fifth, finished off by fellow substitute Sergio Aguero in stoppage time.
"The game was difficult to play, until the second goal," Argentina coach Martino said. "We always had it in our plans for Leo to play 30 minutes though.
"He came on and changed everything. We were lacking a clinical edge and individual spontaneity.
"I enjoy him as much as everyone else does."
Panama were forced to play with 10 men for almost an hour following Anibal Godoy's sending off in the first half.
"The result is exaggerated," Martino added. "Panama played very well.
"It's also true that Argentina has footballers that can change a game in 20 minutes."