Benfica's Augustin Binya regrets his horror tackle on Scott Brown and plans to apologise to the Celtic star.
Binya (right) saw red with five minutes remaining
Binya was shown a straight red card by Swedish referee Martin Hansson for the ugly challenge and Brown was very lucky to avoid a serious injury.
"I tried to look for Scott Brown at the end of the game because I wanted to excuse myself," said Binya.
"I'll try to speak with him by telephone but I also want to take this opportunity to make a public apology."
The dismissal will mean at least a one-match ban but Binya faces the prospect of a longer suspension.
A Uefa spokesman said: "We always open a disciplinary case for a red card."
And Hansson told the Daily Express: "I couldn't say it was the worst tackle I've ever seen because I've refereed a lot of matches and seen a lot of bad challenges.
"But it is certainly one of the worst tackles and there is no doubt in my mind it fully merited a straight red card."
Brown was forced to go off after the challenge and urged Uefa to take further action against the Cameroon midfielder.
A solitary strike from Aiden McGeady kept alive Celtic's aspirations of reaching the last 16 of the Champions League.
But the evening was soured by Binya's malicious stamp with five minutes remaining.
After the 1-0 win, Brown said: "I'm all right. It was a bad challenge but I've come through it.
"I don't think the guy should ever have done that. He obviously tried to do me as hard as possible."
Uefa's disciplinary body next meet on Thursday, 15 November and the spokesman added: "There will be at least a one-match ban.
"But all red cards are judged individually so we will need to wait until the meeting to see if there will be a further ban."