Champions League holders Chelsea began the defence of their title with a hard fought 1-0 win over Zenit St Petersburg.
The Blues struggled to break down the Russian side at Stamford Bridge for 70 minutes, until Romelu Lukaku broke the deadlock.
Lukaku rose highest inside the box to head home Cesar Azpilicueta’s cross to give the hosts all three points.
Bayern Munich travelled to Barcelona, where they crushed the LaLiga giants 3-0 in their own turf.
Thomas Muller’s deflected effort gave the Bundesliga champions a first-half lead, before Robert Lewandowski pounced twice after the break.
Juventus defeated Malmo 3-0, Sevilla played out a dramatic 1-1 draw with Salzburg and it ended 2-2 between Villarreal and Atalanta.