Lisandro Martinez believes Marcus Rashford "can be anything he wants to be" after the forward extended his superb run of form with a sparkling FA Cup display against Everton.
Rashford headed into Friday's tie at Old Trafford having scored in four straight matches, and he played a part in all three of Manchester United's goals as they booked their place in the fourth round with a 3-1 victory over the Toffees.
His cross set up Antony to open the scoring just four minutes in, before more dazzling Rashford work on the wing forced Conor Coady into an own-goal to put United 2-1 up.
Rashford then capped his excellent performance by slotting home from the penalty spot after Alejandro Garnacho was brought down by Ben Godfrey, becoming the first United player to score in seven straight home games in all competitions since Wayne Rooney in 2012.
Rashford spoke after the match on his current form being "up there with the best" he has ever produced, and Martinez feels the sky is the limit for the 25-year-old.
"For me, Rashy is an incredible player," the World Cup winner told Sky Sports.
"He can be anything he wants to be, it all depends on him.
"I see him around the place and he's such a professional. I know how much he gives every day in the training sessions, and I like to think that I'm always there to help him and speak with him if he needs any advice."
Prior to the Everton win, United team-mate Casemiro labelled Rashford a "spectacular" player who can go on to be one of the top five players in the world, and Martinez agrees with the Brazil international, citing the work Rashford carries out for the team as a key part of his game.
"I totally agree with Casemiro," the centre-back explained. "He's a key player for us and he's the sort of player who can turn a game in an instant.
"He's got a great attitude and I think he's going to be one of the best players in the world.
"But it's not just about his individual aspects, it's his work-rate as well. He's got that team ethic and team spirit about him."
Friday's cup triumph was United's seventh consecutive win in all competitions, and Martinez believes players fighting for their places is one of the main reasons for that streak, saying: "I like when there's competition for places, I think it's a positive.
"The vibe and the atmosphere in the dressing room is really positive and I'm proud we're on this good run. It shows we are on the right road and we are making progress.
"Training is even more lively than it's ever been. We can't drop our guard, but three wins and three clean sheets is something to build on."
United boss Erik ten Hag, meanwhile, labelled Martinez as having the personality needed to succeed at the club, and did not hold back in hitting out at some of the club's previous signings over recent years.
"The club has bought an unimaginable number of players in recent years who have not been good enough," Ten Hag told VI Magazine.
"Most purchases have been average and at United average is not good enough.
"United's shirt weighs heavily. Only real personalities, who can perform under great pressure, can play here.
"We needed personalities. That's why the acquisition of Casemiro was so important. Along with Raphael Varane, we now have a second player who has experience of winning titles.
"[Tyrell] Malacia, Martinez, Casemiro, Antony are all fighters, while Christian Eriksen is a technical winner and a great personality. We want the best of the best."
Martinez only returned to Manchester last week after his success in Qatar with Argentina, travelling back to his home nation to join the celebrations before switching his attentions back to club football.
"The celebrations were crazy," Martinez added. "One thing that really hits home is how happy you've made everybody back home.
"Growing up, we've all watched videos of previous World Cups, back in 1978 and in 1986 with Diego Maradona.
"I have to look at images and videos for it to sink in because the idea that we actually won it, to see the enormity of that reality, you have to look at the images to know it's true."