Wenger bemused by touchline ban rules
Wenger sat in the directors' box on Tuesday, serving a one-match suspension for comments made about the referee after last season's defeat to Barcelona, and gave instructions by mobile phone via first-team coach Boro Primorac.
Arsenal had been told this was allowed but UEFA officials then ordered the communications between the manager and the bench to stop at halftime.
"It was difficult because you didn't really know what the rules were. It was a bit confusing. It is a real concern because up to what level can you stop someone doing their job?" Wenger said on the Arsenal website on Thursday.
"I did not feel I had done a lot. We tried to respect the rules as they are set by UEFA but, of course, it is very difficult to see how you can stop someone having an influence.
"What is true is that you can't go to the dressing rooms but I did not do that," said the Arsenal manager.
Wenger now faces a possible extension to his ban which could lead to him missing the second leg of the playoff in Italy next Wednesday. Arsenal won the first leg 1-0.