Shakhtar Donetsk led the way for the Champions League underdogs as they beat holders Chelsea 2-1.
Danish debutants FC Nordsjaelland were within nine minutes of a memorable win over Juventus before having to settle for a 1-1 draw.
Valencia ended BATE Borisov's perfect start in Group F with Roberto Soldado's hat-trick securing a 3-0 win in Belarus.
Last season's beaten finalists Bayern Munich bounced back from a shock defeat by BATE to beat Lille 1-0 in France.
Spartak Moscow moved on to three points in Group G after their first win of the campaign, 2-1 at home to Benfica thanks to Jardel's own goal.
Barcelona needed a goal in the fourth minute of stoppage time from Jordi Alba to beat Celtic 2-1 after the 1967 European champions had taken the lead at the Nou Camp.
Former European champions Manchester United avoided an upset at Old Trafford, coming from behind to beat Braga 3-2 after being 2-0 down inside the first 20 minutes.
In a lively match in Istanbul, Cluj had Matias Aguirregaray sent off after 28 minutes and Felipe Melo missed a penalty for Galatasaray in a 1-1 draw.
- Sports & Recreation
- Shakhtar Donetsk
- Bayern Munich