Arsenal goalkeeper Wojciech Szczesny has been reprimanded by his manager after his offensive hand gesture following his sending off against Bayern Munich on Wednesday.
A further punishment could follow from UEFA who have still to confirm whether they will punish the Pole or not.
Speaking ahead of Arsenal's game against Sunderland Arsene Wenger told reporters: "We will deal with that internally.
"We don't agree with that. Yes, (the gesture) was frustration, but we are professionals, me included, and we have always to master reactions. Wojciech is part of that as well."
The Pole was sent off after clashing with Arjen Robben in the penalty area.
The resulting penalty was missed but the German defending champions dominated with the extra man advantage, winning convincingly.
The red card was Arsenal's 100th since Arsene Wenger took charge in 1996.
Szczesny will be suspended for the second leg in March, where Arsenal have
the difficult job of trying to turn around the two goal deficit.
The 23-year-old has made 33 appearances this season, keeping 17 clean sheets.
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