Arsenal manager Arsene Wenger could be in hot water with UEFA after describing referee Martin Hansson as "incompetent".
Hansson incurred Wenger's wrath during the Gunners' midweek Champions League defeat at FC Porto.
The Swedish official allowed the hosts to take a quick free-kick which ended with Falcao slotting home the winner as the Gunners players were still contesting the decision.
However, Wenger insists the referee made several major errors during the match, saying: "He made at least five technical mistakes for a referee.
"He made a massive mistake that you cannot give a quick free-kick once the referee is in the middle of the action.
"He gave free-kicks in the wrong place. I believe he is incompetent or dishonest, so I prefer to believe he is not competent.
"Usually, I trust the referee. I never have any bad intention but I wanted to understand why he made so many technical mistakes.
"For example, he missed a 100 per cent penalty on Tomas Rosicky. That is a judgement in a second that I can accept but once it gets to a technicality and he has made a decision."