Defending champions Chelsea were stunned 2-1 by Shakhtar Donetsk in a Champions League group E match played on Tuesday, dpa reported.
In the other group game Juventus were surprisingly held to a 1-1 draw at Danish Champions League rookies FC Nordsjaelland.
Donetsk top the group with seven points from their three games, while Chelsea have four - one more than Juventus.
In Group G Jordi Alba scored in the third minute of extra time to secure a 2-1 win at home for Barcelona against Celtic.
Barcelona, who won their 100th Champions League match on the night, have a maximum nine points, while Celtic are on four. Spartak Moscow have three after their 2-1 victory against Benfica in a match played earlier Tuesday.
Manchester United had to come back from two goals down to beat Sporting Braga 3-2 in group G. Alan gave the visitors a two-goal lead within 20 minutes, but Javier Hernandez pulled one back after being set up by Shinji Kagawa in the 25th minute.
Northern Ireland captain Jonny Evans grabbed an equalizer for the Premier League side in the 62nd minute, when the Braga defence failed to clear.
With 15 minutes to go Hernandez gave United the lead for the first time in the game when he headed in his second goal of the night.
The other group H between Galatasary and Cluj ended in a 1-1 draw after the Turkish side missed a first-half penalty against their ten-man opponents.
The win sees United top the group with nine points from Cluj, who have four. Braga have three, while Galatasary have just one.
Group F, meanwhile, remains evenly poised with Valenica, BATE Borisov and Bayern Munich all on six points. The Spanish side, who won 3-0 at Borisov through a Roberto Soldado hat-trick, top the group from Borisov.
Bayern, for whom Thomas Mueller scored the only goal of the game in the first half from the penalty spot in Lille, are third on goal difference.
A further eight matches are scheduled for Wednesday.