- Manchester United ratings: Rashford 8/10 in commanding win
In a game where clear-cut chances were sparse, the highlight of a dull opening quarter came when a streaker somehow managed to find his way onto the pitch, despite crowds not being allowed to attend the match due to COVID-19 protocols.
Rashford's goal just past the half hour was the game's standout piece of quality.
Victor Lindelof strode out of defence and his long ball was perfectly weighted into the path of the England forward, who controlled well before coolly finishing to put United ahead and notch up his 20th goal of the season in all competitions.
Granada fought valiantly for a way back into the game, with Chelsea loanee Kenedy testing David de Gea from long-range before Yangel Herrera -- on loan from Manchester City -- hit the post with a volley.
In a cagey second-half Fernandes, denied a second goal by a save by Portuguese countryman Rui Silva from close range late on, then netted a stoppage-time penalty after being felled by substitute Yan Brice Eteki.
The return leg is next Thursday at Old Trafford and the winners of the tie will face the victors in Ajax Amsterdam's clash with AS Roma in which the Italians hold a 2-1 lead from their first away leg which was also played on Thursday.