Jose Mourinho fumed at officials following Real Madrid's 1-1 draw at Lyon in the Champions League, claiming a missed handball could prove decisive in the round of 16 tie.
Karim Benzema scored against his old club before Bafetimbi Gomis' last equaliser kept the tie wide open ahead of the second leg in Spain, but it could have been a different story had the expanded referee team awarded a penalty when Cristiano Ronaldo's free kick appeared to hit a defender's arm just after the hour mark.
"It's difficult to be a referee and there are errors in matches that are due to fatigue or slowness to react," Real Madrid boss Mourinho said. "These are the errors we have to accept. After, there are other errors that you can't accept. There was a free-kick and in the slow-motion replay you can see it clearly.
"I was 50 yards away and I could see it. He (Stark) was five yards away with all his assistants and he didn't. I don't understand. It could still be decisive in the tie. I just hope it won't be."
Mourinho admitted though that 1-1 was a score he was happy to take back to the Bernabeu against an opponent that has proved to be something of a bogey team for Madrid.
"My team has no fear; today we have already changed the direction of history a bit," said Mourinho. "We scored for the first time here, we have drawn for the first time too. It is 50-50 but this is a positive result."
He added: "Everything is left open against a quality opponent but I hope the Bernabeu helps the team create a magical European night."
Lyon boss Claude Puel wondered whether his team might be punished for their failure to record a more dominant scoreline before travelling away in the second leg.
"At home in the first leg, we would have preferred them not to score. It's a bit of a shame, especially because we played a great first half," said Puel. "At times we were a bit lacking in the final ball, be it the final pass or the final shot.
"In the first half they created very few chances. We were less solid defensively at the beginning of the second half, but we were able to pull the game back at the end. It will give us confidence ahead of the return leg, even though we would obviously have preferred not to have conceded a goal to them."