Marcus Rashford has a liking for the big occasion in the Europa League, and for all the impact he made on his debut in this competition last season, scoring twice against FC Midtjylland, his match-winning contribution in Thursday's quarterfinal win against Anderlecht has taken the 19-year-old to a whole new level.

Mourinho's affection for the United youngster is obvious whenever he speaks of his player's attitude, performance and contribution.

The former Chelsea manager calls Rashford "the kid." But with United into the Europa League semifinals and fighting for a place in the Premier League top four, Mourinho needs Rashford to become "the man" because top United scorer Zlatan Ibrahimovic (28 goals) suffered a nasty-looking knee injury in the final minute of normal time against Anderlecht, the Belgian league leaders.

Ibrahimovic will undergo tests Friday, and a full prognosis may not come until the weekend if swelling does not subside sufficiently over the next 24 hours.

Mourinho said the outlook is "fairly negative" for both Ibrahimovic and defender Marcos Rojo, who was carried off in the first half, so somebody else has to shoulder the goal-scoring burden in the short term at the very least. United will turn to Rashford.

"[Rashford] cannot play every game and, at the top of that, [England] are trying to take him for the European under-something tournament, no?" Mourinho said. "It is hard for the kid to play every match, but I always trust the players with a special mentality.

"You speak about his qualities, and they are fantastic, but with his mentality, he is excellent.

"He hadn't scored since September. Some players don't understand what I want, what it takes for me to trust a player, but Marcus I trust. It doesn't matter if he doesn't score -- he is fantastic in his effort and attitude."

A year ago, Rashford's goals and youthful energy carried Louis van Gaal's United over the final months of the campaign and played a significant role in their FA Cup triumph. Back then, he hit eight goals in 18 appearances as an unknown rookie and earned himself a call-up to England's Euro 2016 squad.

Year 2 was always going to be more of a test, but while it would be an exaggeration to suggest that the young Mancunian has suffered a severe bout of so-called second-season syndrome, it has certainly been a more difficult campaign than he would have imagined.

Marcus Rashford has returned to peak form when Manchester United need him most.

The goals have not flowed quite so readily, with none in the Premier League between his strike against Leicester in September and the final goal in a 3-0 win at Sunderland earlier this month.

But Mourinho has largely stood by Rashford, believing that his pace and direct running offer more than goals, but also the ability to stretch opponents and create space for others.

Mourinho's faith in Rashford is underlined by the fact that only Paul Pogba (46) and Ibrahimovic (46) have made more first-team appearances than Rashford (44) this term.

But while Ibrahimovic was fit and scoring, Mourinho relied on the Swede to lead the line and carry the team.

That option now looks likely to have gone, but Rashford's sensational performance during Sunday's 2-0 win against Chelsea in a central role had already set in motion the campaign for the youngster to take Ibrahimovic's place even before injury struck the 35-year-old.

Mourinho now has Rashford, Anthony Martial and Wayne Rooney at his disposal, if the initial fears of a lengthy layoff for Ibrahimovic prove to be correct, and Rashford is undoubtedly the main man.

Zlatan Ibrahimovic suffered a nasty-looking knee injury in Man United's win over Anderlecht on Thursday.

Retired star Michael Owen, who knows a thing or two about being a teenage striking sensation, spoke on BT Sport after this game about Rashford's quality, how he is "brimming with confidence" and deserving of the chance to play through the centre.

Rashford missed a big chance against Anderlecht with the score at 1-1, but as Owen insisted, "You don't worry about those when you're 19; it's when you are 29 that you think about things too much."

It proved to be so when, early in the second half of extra time, Rashford collected Marouane Fellaini's knockdown and took a touch before guiding his shot beyond Anderlecht goalkeeper Martinez Ruben.

That made it two in two games, following Rashford's goal against Chelsea, so perhaps his scoring form is just beginning to return in time for the decisive stage of the season.

He is still a kid, with his 20th birthday not until Halloween, but Mourinho knows this kid has the ability to perform beyond his years.

And the reality is that, starting now, he really has to if United are to win the Europa League.