Speaking on Sky Sports, Jamie Redknapp said: "All the best players have the rascal gene — you don't want to have a team of Gary Nevilles.
"The greats have a bit of devilment about them. Look at Wayne Rooney. Sometimes, it doesn't always add up, but they do things differently. You need match-winners and that's what he is.
"If you go through the greats in history, most in history have a bit of genius and madness alongside it. Alejandro Garnacho has the world at his feet now.
"You hear so many rumours about this young man for a long while, about the talent he possesses and he's just shown it on the world stage."
Although there were major question marks about Garnacho's attitude at the start of the season, the 18-year-old is now on the verge of breaking into Manchester United's first team.
Last week, the young winger came off the bench to provide two assists in the 4–2 win against Aston Villa in the Carabao Cup before scoring the winning goal in the 2–1 win away at Fulham in the Premier League.
