Former Manchester United defender Gary Neville has claimed that Anthony Martial "could do anything" in the game if he showed "that extra 15%" during matches.
Martial was United's hero on Saturday afternoon as the Frenchman came off the bench to score the winner against Tottenham Hotspur at Old Trafford.
It was the 21-year-old's fourth Premier League goal of the season, but he has struggled to hold down a regular starting role for Jose Mourinho this season - sharing the left flank with Marcus Rashford.
Neville has insisted that the Frenchman has the ability to become one of the best players in the world, but wants to see more from the former Monaco attacker on a consistent basis.
"It's been a stop-start Manchester United career for Martial. For someone of his talent, he should be tearing this league apart with his ability. He's lost his place in the France squad - there's obviously something wrong with him," Neville said on The Gary Neville Podcast.
"Mourinho and the French manager has turned off of him a little bit. You always get the feeling he's playing at 85%. If he showed that extra 15%, then he could do anything. He's got everything you'd want: composure in front of goal, great skill, pace, strength, but what is that little bit missing?
"The best players in the world don't have 'but's' - the likes of Luis Suarez, Cristiano Ronaldo, Lionel Messi - there are no buts. Martial is well off that category but that's where he's got to be looking.
"He's worth £50m and with that talent, he's got to step up. He scores in big games, he takes big moments on and obviously has the temperament to play in big games. But come on, let's see it every single week. He could be a player that could score 20 goals in 20 games if he really wanted to and strived to be the best."
Martial has managed 31 goals in 105 appearances for United since a move from Monaco in the summer of 2015.