That is the verdict of BT Sport pundit and former Manchester United and England midfielder Paul Ince.
Martial put pen to paper on a new deal on Thursday to keep him at Old Trafford until 2024.
The news comes just six months after his agent confirmed the forward wanted to leave the club.
Martial fell out with former manager Jose Mourinho in pre-season after failing to return to the tour of the USA following the birth of his son.
But the Frenchman has been a regular under interim boss Ole Gunnar Solskjaer, starting five of the six Premier League matches since the Norwegian was appointed in December.
Ince is pleased to see Martial end speculation over his future and commit himself to United.
But he admits there is plenty of improvement with his game that is still needed.
“You’d like to think so [it’s the start of a new era],” Ince said.
“You probably think that two or three months ago Martial was reported to wanting to leave the club and go somewhere else according to his agent.
“So obviously with the fact he has now put pen to paper on a five-year contract, it’s great for the club, great for the fans.
“He needs to do a bit more. I still think there is a lot more, he’s only young he’s 23, but he needs to do a lot more.”
Martial missed the 2-2 draw with Burnley on Wednesday due to injury.
But he is set to return to the squad for the trip to Leicester on Sunday.
Paul Pogba has made the journey to the East Midlands despite being an injury doubt.
But Antonio Valencia, Matteo Darmian and Chris Smalling will all miss the match.
Leicester head into the clash after the 1-1 draw with title-chasing Liverpool on Wednesday.