Gomez gave Bayern the lead just before halftime when Robben’s defence-splitting pass sent him clear and his shot beat Elinton Andrade who should have done better.
The Bundesliga side, whose stadium will stage the final, dominated the second half and Robben doubled their lead after 69 minutes when he played a neat one-two in the box with Thomas Mueller before cooly slotting the ball past Andrade.
Marseille had a few early chances, notably when Rod Fanni’s header was parried by Manuel Neuer into the path of Loic Remy only for the France striker to lash his close-range shot wide.
The second leg takes place next Tuesday.
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