Jose Mourinho's side had laboured throughout the game against the Swiss champion at Old Trafford and looked set for a second consecutive goalless draw at home until Fellaini's smart finish.

Indeed, it could have been worse for United had David de Gea not produced a stunning reaction save to keep out a deflected effort from substitute Ulisses Garcia in the second half.

The result, coupled with Valencia's 1-0 defeat to Juventus, means the Red Devils join the Italians in booking a spot in the knockout phase with one group game to spare.

Mourinho had threatened to make changes to the team that drew 0-0 with Crystal Palace and followed through, with Paul Pogba and Romelu Lukaku benched and Alexis Sanchez left out of the squad.

Marcus Rashford led the attack and spurned four decent first-half opportunities with poor finishes, the worst of which saw him lifting the ball over goalkeeper and crossbar when put through one on one by Jesse Lingard.

Fellaini blazed over after some poor goalkeeping from David Von Ballmoos early in the second half, but United was otherwise looking toothless in the final third, as they surpassed its club record of 231 minutes without a goal at home in the competition, set back in 1996-1997.

Mourinho introduced Romelu Lukaku and Paul Pogba from the bench and the latter set up Rashford for another half-chance the striker sliced wide, before De Gea somehow clawed the ball off his line after Garcia's shot went through a crowded box.

United fans were already heading for the exits when Fellaini at last gave them something to cheer, collecting Lukaku's flick-on and firing across goal and into the bottom-left corner from 12 yards.