Arsenal defeated Leuven 3-0 on Wednesday, but will face the Belgian debutants again in February for the play-offs.
If successful, they will face Chelsea in the quarterfinal, with the reigning Women's Super League holders earning a direct path to the knockouts after finishing the league phase in third.
After three years of meeting foes Barcelona in the semifinals, Chelsea have been drawn on the opposite side to the three-time winners and will avoid facing them in the semifinals if they were to get there. They drew 1-1 in the league phase and now can only meet again in the final.
Manchester United, also in their debut campaign, finished the league phase in sixth and have been drawn against Atletico Madrid. United defeated the Spanish side 1-0 in a fiery clash in the league phase.
A quarterfinal against Bayern Munich will await them if successful, with a possible semifinal clash against either Paris FC, Real Madrid or Barcelona.
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