Reigning champions Real Madrid beat APOEL Nicosia 3-0 with Cristiano Ronaldo straight back in the goal-scoring groove.
Ronaldo is currently serving a domestic ban for pushing the referee after being sent off in the Spanish Supercopa clash with Barcelona last month.
But the Portuguese superstar scored twice on his return - taking his Champions League career goals tally to a record 107 - and Sergio Ramos added a spectacular overhead kick.
Elsewhere in Group H, Tottenham beat Borussia Dortmund 3-1 at Wembley, with Harry Kane scoring twice.
John Stones also netted twice as Manchester City produced an outstanding performance to open their seventh successive Champions League campaign with an emphatic 4-0 win at Feyenoord.
City now have back-to-back home Group F games against Shakhtar Donetsk and Napoli and it is the Ukrainians who have joined Pep Guardiola's side on three points.
Shakhtar won 2-1 against Napoli with Taison and Facundo Ferreyra on target, before the Italian side's Arkadiusz Milik grabbed a consolation from the penalty spot.
While Liverpool were held 2-2 at home by Sevilla in Group E the other game in the group saw Spartak Moscow draw 1-1 at NK Maribor, Aleksandr Samedov putting the Russians ahead before Damjan Bohar equalised five minutes from time.
In Group G, Monaco drew 1-1 at RB Leipzig with Emil Forsberg's goal for the hosts quickly cancelled out by Youri Tielemans.
Besiktas won 3-1 at Porto with Talisca, Cenk Tosun and Ryan Babel all on target. Porto's consolation came from a Dusko Tosic own goal.