Spanish football champions Real Madrid pulled off a stunning Champions League comeback when they twice fought back from a goal down to beat Manchester City 3-2 in Madrid.
All the goals came in the second half with City scoring what appeared to be the winner five minutes from time.
However Cristiano Ronaldo netted a 90th-minute winner to ease some of the pressure on their manager Jose Mourinho.
Meanwhile Arsenal came from behind to win 2-1 in an end-to-end game at Champions League debutants Montpellier.
Paris St Germain produced some brilliant football to make a dream start to their campaign with a 4-1 home win against Dynamo Kiev, while newcomers Malaga beat Zenit St Petersburg 3-0 and former Champions League holders Porto won 2-0 at Dinamo Zagreb.
In a clash of ex-European title winners Borussia Dortmund beat Ajax Amsterdam 1-0 while seven-times European champions AC Milan were booed off after a 0-0 home draw against Anderlecht.