The Red Devils returned to winning ways in style as they put one foot in the next round of the Europa League with a comfortable victory.
Bruno Fernandes put Solskjaer’s men ahead inside the opening 27 minutes.
The Portuguese doubled the English side’s advantage with his second goal twelve minutes after the interval.
England forward Marcus Rashford and Daniel James scored on 65 and 90 minutes respectively to compound the Spanish side’s misery.
Manchester United are now unbeaten in their last nine away games across all competitions (W5 D4), while they have kept a clean sheet in four of their last six.
"We scored some good goals and played some nice football. We deserved to win but maybe not by four goals. On a night like this when we find spaces we can be a dangerous team,” Solskjaer told BT Sport after the game.
"We had to defend well, they have some terrific players up front and we earned the right to counter-attack quickly. They opened up and we got the spaces we wanted.
"Every team attacks you, it's about finding the moments to find the space. We are a work in progress, we are learning and some games we have not been able to win lately."
Next up for Manchester United is a game in the Premier League against Newcastle United on Sunday.
