Arsenal boss Arsene Wenger fears they will struggle to win penalties in the Champions League because of the Eduardo controversy earlier this season.
The Croatian was adjudged to have been fouled by Celtic goalkeeper Artur Boruc in the match at The Emirates.
Celtic were incensed and UEFA handed Eduardo a two-match ban for diving.
Arsenal protested and had the suspension lifted on appeal, but Wenger now feels there could be a backlash.
"Yes, I am worried," he said. "It was 100 per cent a penalty on Carlos Vela in Alkmaar and also one for Robin van Persie in Alkmaar.
"I fear completely that we may not get the penalties we should after Eduardo.
"Some referees may go into the game with what happened in their mind.
"What happened with Vela was unbelievable. I hope what happened with Eduardo is not an influence but it did come into my mind after the game. Eduardo was a big case."
