Arsenal claimed victory from the jaws of defeat with a late strike from substitute Lukas Podolski in Belgium.
Anderlecht took the lead with a header from Andy Najar in the second-half, and it looked like the hosts would claim a crucial victory on Arsene Wenger's birthday.
However, Kieran Gibbs scored an 89th minute equaliser, before German forward Podolski fired home to secure an unlikely victory in Group D.
It looked like it would be a night to forget, but things look a little brighter at the Emirates Stadium tonight. Here are the GiveMeSport player ratings...
Emiliano Viviano - 7
Considering the young Argentine is the third-choice keeper for Arsenal, he did little wrong all night, had no chance with the goal and made some decent saves in the second-half.
Calum Chambers - 6
Per Mertesacker - 6
Nacho Monreal - 5
It's hard to blame the Spaniard for a pretty poor performance, given the he's a full-back, but better opposition will expose the defender if he plays at the heart of defence again.
Kieran Gibbs - 7
Occasionally looked shaky in defence, but was a threat going forward and got his reward with a beautiful finish.
Mathieu Flamini - 6
Jack Wilshere - 6
Aaron Ramsey - 6
Alexis Sanchez - 8
Produced the cross for Podolski's winner, and whilst his final ball and finishing could have been better, he was the man of the match for the Gunners.
Santi Cazorla - 6
Danny Welbeck - 6
SUBS: Alex Oxlade-Chamberalin, Joel Campbell, Lukas Podolski - 8
Freshened things up when required in the second period, with Podolski grabbing the winner in the final moments.