We tried to win the match but we missed chances, but the team played well.
"The free-kick is work".
Mourinho, however, said that although he was happy with his side's performance against Celta Vigo, he does not feel the same way about the result.
"I think if you ask his teammates, they would probably prefer to play with Rashford upfront".
The Premier League side take a one-goal lead back to Old Trafford to face Celta Vigo thanks to Rashford's wonderful freekick at the Estadio Municipal de Balaídos.
The former England worldwide overstretched his hamstring as he attempted to block a cross and went down holding the back of his thigh. It overcame a 1-0 loss at home in the round of 32 to Shakhtar Donetsk, and advanced by 2-0 win in the second leg. Celta also defeated Real Madrid away from home in the Copa del Rey, and eventually eliminated Madrid.
Alvarez then thwarted Henrikh Mkhitaryan and Jesse Lingard in one-on-one situations in quick succession before the break as United midfielder Paul Pogba's influence began to grow.
"So for me not a problem at all and I think he will be really pleased with me that I am going to change my team against Arsenal".
Mourinho said: 'The players that are in accumulation, the players that are with lots of minutes because we played nine matches in April and this one, so 10 matches in four-and-a-half weeks. "He had a fantastic shot in the first half, and then that handsome save".
Celta's frustration spilled over in the closing stages as United ran the clock down efficiently.
"We are going to have to go there and score goals, as we did other times", Celta coach Eduardo Berizzo said. They have bigger guys, we have smaller guys and we're good at different things.
United are bidding to win the Europa League for the first time and guarantee a place in next season's Champions League in the process.
"The Man United fans expect more than sitting back and taking a 0-0 draw so I think we are going to have even more space, although we should have probably kept it 0-0".
"We know we can do it", he emphasized.