The Manchester United manager presided over a narrow Europa League semi-final first leg win over Celta Vigo on Thursday and believes winning that competition represents his side's best chance of qualifying for the Champions League next season.
Rashford also had to be substituted, but Mourinho said that was a result of a problem he carried into the game.
"He is a kid who stays after training for half an hour more to practice taking free-kicks and waits for the opportunity". He works, he works, he works. He works, works, works, and is very mature.
The 2016-17 Europa League final will be held in Guidetti's home city of Stockholm at the Friends Arena national stadium on May 24th.
"It's part and parcel of football", he said.
Manchester United, England's last European representatives, have travelled far and wide in their bid to win the only major continental trophy to have eluded them in their success-laden history.
The victor of this tie will meet Ajax or Olympique Lyon in the final at the Friends Arena in Stockholm on Wednesday, 24 May.More news: Deepika Padukone at Cannes Film Festival 2017 Trending Viral Images
United manager Jose Mourinho looks set to continue with his plan to rest players for Sunday's match with Arsenal. Tonight they were not superior, we were close and it's not impossible (for us to progress).
"The free-kick is fantastic and I don't think the goalkeeper has any chance because the shot is very fast". "It was a good performance".
'But the opponent was hard, the match was hard, the stadium was hard, so I can not be happier with the players and their work.
Rashford has scored four times in under a month including a dramatic extra-time victor against Anderlecht in the quarter-finals, his form coming at a vital time with Zlatan Ibrahimovic out injured.
'I am going to change my team to play against Arsenal, so I think Wenger will be really happy with me, ' says Mourinho.
It was a mostly even match in front of almost 30,000 fans at Balaidos Stadium, but United had most of the significant chances.