Robben helped Bayern outclass Manchester City 3-1 away, a demonstration that Bayern's defense of the title is right on track with two wins from two games.
"We controlled the match and that is important in the Champions League," Bayern's coach Pep Guardiola said.
Ronaldo and Angel Di Maria scored two goals each for Real Madrid in a 4-0 rout of Copenhagen, while Zlatan Ibrahimovic notched a brace for Paris Saint-Germain in a 3-0 demolition of Benfica.
Ronaldo's two goals against Copenhagen raised his total for two games to five, following a hat trick in a 6-1 win at Galatasaray on the opening matchday.
Madrid coach Carlo Ancelotti said he was pleased with the game, saying it had a good beginning, intensity and balance.
Copenhagen coach Stale Solbakken praised Ronaldo, saying: "He is the man of the match with his two goals."
With 10 goals in two matches and six points Real is firmly in control of Group B, ahead of Juventus with two points.
Juventus nearly picked up all three points on the night when substitute Fabio Quagliarella made it 2-1 with an 87th minute header -- only for Didier Drogba, who had earlier put the Turkish side in front, to find Umut Bulut for an immediate equaliser.
