The midfielder saw red in the 88th minute of Barca's 2-0 victory against Benfica in the Group G of the tournament last week.
Busquets was given his marching orders for a rash challenge on Benfica captain Maxi Pereira.
He will now miss the clash against the Scottish champions at the Camp Nou on October 23 and the return fixture in Glasgow on November 7.
He has three days to appeal the ban.
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