Arsenal manager Arsene Wenger will find out on Thursday if he faces the prospect of a third touchline ban from UEFA within the space of a year.
Wenger was unhappy with the performance of Damir Skomina in Tuesday night's 3-0 win over AC Milan, angrily confronting the Slovenian official after the game on the pitch at the Emirates Stadium.
Wenger claimed the referee gave away too many free-kicks away to the Italians, who progressed to the quarter-final stage with a 4-3 aggregate win.
UEFA will decide whether to charge Wenger based upon the information they receive in Skomina's report, which has to be filed within 48 hours of the end of the match.
European football's governing body said they do not expect to receive the report today, however.
A UEFA spokesman said: "It will be tomorrow before we know."
Wenger made his thoughts clear on Skomina's performance in his post-match press conference, saying: "I was not happy with the referee tonight because I felt he gave many free-kicks in the middle of the park.
"Every time they went down a free-kick was given for them, and they sensed that very quickly and they used it very well."
UEFA handed Wenger a one-match touchline ban for an on-field rant at Massimo Busacca following his team's last-16 exit to Barcelona last year. The Arsenal boss was fuming at the Swiss referee's decision to send off Robin van Persie.
Wenger was then handed a further two-match touchline suspension for violating his Barcelona ban by communicating with the Arsenal bench from the stands during the Gunners' playoff tie against Udinese earlier this season.