Jose Mourinho in the dark over Marcus Rashford's knee injury after Manchester United's matchwinner limps off in Lisbon

The 19-year-old scored the only goal of United's win at Benfica but limped off shortly after

Marcus Rashford scored Manchester United's winner in Lisbon before limping off with a knee injury (Manchester United)

Jose Mourinho is hoping for the best after Marcus Rashford limped off with a knee injury but admits his Champions League's match-winner diagnosis remains firmly up in the air.

The 19-year-old scored the only goal of Manchester United's win at Benfica after his free-kick caught out teenage goalkeeper Mile Svilar in Wednesday's Champions League encounter.

But shortly afterwards Rashford sat frustrated on the deck with a knee injury that forced him out of the Group A clash.

"Marcus Rashford, I thought was cramps because he was running so much that I thought it was about muscular fatigue," Mourinho said. "But, no, he told me he was feeling something in his knee. It didn't look for me a big thing but you never know."

Mourinho, meanwhile, defended his side's cautious approach after coming in for criticism in recent weeks.

"You know, with other managers, with other players, I'm pretty sure that yes (they get an easier ride) but that's not the problem for us," he added. "And there is another situation, maybe I'm guilty of it: I never speak about injuries. Other managers, they cry, they cry, they cry when some player is injured. I don't cry.

"I think the way to do it is to ignore the players that are injured, is to focus on the players that are available. it is to give confidence to the players that are available. But if I want to moan and cry like the others, I can cry for the next five minutes.

"(Zlatan) Ibrahimovc, (Paul) Pogba, (Marouane) Fellaini, Marcos Rojo - I can cry but I don't, so we do it with what we have. You know, we went to Liverpool with two midfield players and nothing else, not even on the bench.


 Rashford's goal gave United a priceless away win 
 (Getty)

"Today it happened the same. We brought a kid, like Benfica does, because I don't have another solution. I brought Scott McTominay who is the same age as Benfica's kids, but the Premier League is a different story. It's really hard.

"But, again, you know, 12 matches, 10 victories, two draws, nine clean sheets. We are not bad."