Arsene Wenger has accused UEFA of "accepting doping" after failing to punish Dinamo Zagreb for fielding a player who subsequently failed a drugs test in the Champions League clash between the sides last month.
Arijan Ademi played the full 90 minutes as Dinamo beat Arsenal 2-1 in their Group F opener on September 16 but then tested positive for a banned substance in the post-match drugs test.
UEFA banned Ademi for four years but the result was allowed to stand with the current ruling from European football's governing body stating that two or more players have to have been found to have doped for sanctions to be imposed.
Asked if he found that stance surprising, 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, because you cannot say 'okay, they are the doped players and the result stands' because it means you basically accept doping.
"But it is the rule and we accept that and we have to look at ourselves and deal with our own performance."
Wenger has been outspoken on the topic of doping in recent weeks, and hinted his views may have prompted a visit from UEFA drug inspectors last week.
He added: "I came out on that. As a result we had a doping control from UEFA on Friday. We had 10 people to control us."
Dinamo have publicly backed Ademi and coach Zoran Mamic hinted his player was given a more severe punishment because he did not play for one of Europe's big clubs.
"We are all shocked," Mamic said. "This is idiocy to punish a lad like this after he and experts have proven his supplement was polluted and accepted that he didn't know about it.
"Yes, he should have been more careful, the rules are strict, but to suspend him for four years is idiocy. And I wonder what would the fine be if it was some Arsenal, Manchester United, Bayern Munich or some other high-ranked club's player?"