Arsenal manager Arsene Wenger has demanded UEFA change their rules on doping because he claims the current regulations don't do enough to discourage drug cheats.
Wenger has been outspoken against doping and questioned why UEFA rulings means there is no way of disqualifying a team from continental competition unless more than two players fail a test.
His frustration has come to the fore this week as Dinamo Zagreb midfielder Arijan Ademi was handed a four-year ban for failing a drugs test after the Croatian side beat Arsenal in the Champions League in September.
Zoran Mamic's side won 2-1 in Zagreb and now Arsenal face them again at the Emirates Stadium on Tuesday knowing they must secure a victory to stand any chance of getting out of their group.
Asked on Monday if he found the regulations strange, Wenger said: "Yes, of course.
"It's a surprising rule. UEFA applies the rule that is planned but I personally don't agree with the rule.
"You cannot say that they had a doped player but the result stands.
"That means you basically accept doping. But it is the rule and we accept that. We have to look at ourselves and deal with our own performance."
The Frenchman believes the rules need to be altered but admitted he did not know how much public backing he would receive after seeing UEFA's doping team visit Arsenal's training ground shortly after his recent comments.
"I don't know if I would have the support of anybody but I came out on that and as a result we had a doping control from UEFA on Friday," he added.
"We had 10 people on Friday to control us. I do not want to speculate too much on the career of a player. In between (the match in September and now) he has been punished. There are two things: our performance on the day and the fact that they had a doped player."
That loss against Dinamo in Croatia was the first of three damaging defeats in Arsenal's first four Group F matches which have left their European hopes hanging by a thread.
Even victory on Tuesday may not be enough if Bayern Munich fail to beat Olympiakos in Germany.
Arsenal's cause hasn't been helped by an injury to French midfielder Francis Coquelin, who will be out for at least two months with a knee problem.
"It is at least two months but I'm cautious as we had so many bad surprises on scans that I do not want to speculate more than that. Certainly for the next two months we play without Coquelin," Wenger said.