Lionel Messi will remain world's best as long as he plays says Lionel Scaloni

KANSAS CITY: Argentina head coach Lionel Scaloni believes Lionel Messi will continue to be the world's best player for as long as he decides to keep playing, dismissing any doubts over the veteran forward's ability despite approaching his 40th birthday.

Messi has played a pivotal role in Argentina's FIFA World Cup campaign, scoring eight goals to sit level with France's Kylian Mbappe in the Golden Boot race.

The 39-year-old also inspired Argentina's remarkable 3-2 comeback victory over Egypt in the round of 16, scoring once and setting up Cristian Romero after his side had trailed 2-0 with only 11 minutes remaining.

The Inter Miami star entered the tournament amid concerns over his fitness following a recent muscle strain, but Scaloni said he has not been surprised by his captain's physical condition.

"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 insisted those expecting age to slow Messi down underestimated the Argentine captain.

"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 will face Switzerland in Saturday's quarter-final in Kansas City after the Swiss reached the last eight for the first time in 72 years by defeating Colombia on penalties following a goalless draw.