sights of goal for the Reds and Moyes was out on the touchline after a chance was created by Carlos Bacca.
Two goals in four minutes then silenced the home crowd as some slick football cut open the United defence. Bacca fed Perotti, who swiftly released Vitolo and the No20 beat David De Gea to stab the ball home. Soon afterwards, Vitolo was unselfish after another fine pass by Bacca and squared to hand Marin a simple tap-in.
Marin, on loan from Chelsea, whistled another shot just wide and United were stung into action with Shinji Kagawa unable to collect a cute pass by Fabio. Büttner's deep cross beyond the back post was volleyed across by Valencia but Kagawa saw his header from the most inviting of positions somehow scrambled away by Beto on the line.
After going so close to reducing the deficit, it could easily have been worse for the Reds as Marin sped past Chris Smalling and saw his goalbound shot diverted onto the bar by De Gea's boot with five minutes of the first half remaining. Bacca blazed over when Diogo Figueiras was afforded far too much space on Sevilla's right before Valencia spurned the final opening before the break, lashing high and wide after Anderson picked him out inside the box.
United upped the tempo from the restart with Januzaj, now working hard in a lone striker's role, lifting over a curler from an Anderson pass. It proved only a taster of what the teenager is capable of as he played a key role in Valencia's goal. Collecting a pass from substitute Jesse Lingard, he forced a diving save out of Beto and latched onto the rebound, dribbling past Israel Puerto with ease to cross for Valencia to convert from a couple of yards out.
It proved to be the Ecuador winger's last contribution as manager Moyes made three substitutions but Januzaj and Lingard continued to impress,