Argentina coach Lionel Scaloni said on Friday he is not surprised by Lionel Messi's physical condition at 39, reiterating that he believes the captain will remain the best player in the world for as long as he chooses to keep playing.
Messi has been instrumental in Argentina's World Cup campaign, scoring eight goals — level with France's Kylian Mbappe — and inspiring a dramatic 3-2 comeback victory over Egypt in the round of 16.
Against the North Africans, the Argentine talisman — playing in a record sixth World Cup — netted once and provided an assist to Cristian Romero after his side trailed 2-0 with 11 minutes remaining.
The Inter Miami forward, who turned 39 last month, arrived in the tournament with questions over his fitness after recently recovering from a muscle strain.
"Leo runs more or less the same in every match," Scaloni said. "Physically, it's true that he has done preparation work with his fitness coach and it has paid off, but in terms of numbers I don't know if he has changed that much."
"What is clear is that he's giving everything he has. When he gives everything he has and senses that he can create danger, he is a machine," the coach added.
Scaloni said those expecting age to catch up with Messi did not know the player well enough.
"It doesn't surprise me," he said.
"Maybe people who don't know him expected that at 39 he wouldn't be at this level, but I don't know how many times I've said it: as long as he wants to, he will be the best. I think that, and not because I'm his coach."
Argentina face Switzerland in the quarter-finals on Saturday in Kansas City. Scaloni praised their opponents, who reached the last eight for the first time in 72 years after eliminating Colombia on penalties following a goalless draw.
"There are no easy rivals, we all know that," Scaloni said.
"They are a very good team. They compete with the best national teams and always come through. They may win or lose, but they always compete. They have World Cup tradition, experienced players and are physically strong."