UEFA have fined Arsenal €15,000 (£12,966) for a late kick-off and a pitch invasion in their Europa League game against Qarabag at the Emirates Stadium in December.
An individual came onto the pitch during the match carrying the flag of the disputed Nagorno-Karabakh region, which has been central to conflict between Azerbaijan and Armenia.
Qarabag are an Azerbaijani team originally based in Agdam, but have not played in their hometown since 1993 due to the Nagorno-Karabakh war.
Arsenal midfielder Henrikh Mkhirtaryan, who is from Armenia, was left at home for the away game against Qarabag because of the tensions between his country and Azerbaijan.
Arsenal won the match at the Emirates Stadium 1-0 on their way to finishing top of Group E, while Qarabag finished bottom of the table and exited the tournament.
However, the Gunners were beaten 3-1 by Rennes in the first leg of their last-16 tie on Thursday, leaving them with a difficult task if they are going to make the quarter-finals.