Celtic suffered their worst ever European defeat as Barcelona thumped seven past the Scottish champions at the Nou Camp.
Lionel Messi was unstoppable, opening the scoring in the third minute and going on to a hat-trick.
Celtic missed a penalty that might have given them hope but on the night the Spanish giants were simply unstoppable.
Arsenal went behind in the first minute of their Group C tie against Paris St Germain but weathered the storm in Paris to clinch a draw and a valuable point away from home.
Napole were 2-1 winners away to Dynamo Kiev.
Bayern Munich, under new coach Carlo Ancelotti, hit five past Russian side FC Rostov.
Also in Group D Atletico Madrid won 1-0 at PSV Eindhoven.
Benfica were held to a 1-1 draw at home to Besiktas.
Swiss side Basel could only draw 1-1 at home to Ludo Razgd.
There was drama at the Etihad as heavy rain, thunder and lightning hit Manchester on Tuesday evening, forcing the Group C match against Borussia M’Gladbach to be abandoned because of adverse weather. That game will be played tonight.
Tonight’s Champions League fixtures.
Man City 19:45 B M’gladbach
Tottenham 19:45 Monaco
Club Brugge 19:45 Leicester
Bayer Levkn 19:45 CSKA Moscow
Legia War 19:45 Bor Dortmd
Real Madrid 19:45 Sporting
FC Porto 19:45 FC Copenhagen
Juventus 19:45 Sevilla
Lyon 19:45 Dinamo Zag