Sir Alex Ferguson's side were in danger of an embarrassing defeat after two early goals from Braga's Alan shocked Old Trafford.

But Hernandez sparked United's revival with his first goal before half time and the Mexican striker bagged the winner with 15 minutes remaining after Jonny Evans equalised just after the hour.

Chelsea's hopes of a place in the last 16 were compromised when the holders fell to the first loss of their trophy defence in a 2-1 defeat at Shakhtar Donetsk.

Despite a late effort by Oscar, goals from Alex Teixeira and Fernandinho were enough to give the Ukrainian champions breathing space at the top of Group E.

Chelsea remain in second place but are now three points behind Shakhtar ahead of the return game on November 7.

Jordi Alba scored with almost the last kick of the match as Barcelona snatched a 2-1 comeback win at Nou Camp to Celtic in Group G.

The Scottish champions took a 18th-minute lead through Giorgos Samaras' header.

But Barca's Andres Iniesta combined with Xavi and squeezed a shot just inside Fraser Forster's post in the 45th minute to score.

Then Jordi Alba popped up at the far post in the 94th to deflect Adriano's cross over the line.

Thomas Mueller's first-half penalty proved enough to secure Bayern Munich a 1-0 win at Lille in Group F.

Bayern, BATE and Valencia all have six points from three matches, with Lille yet to claim a point.