Celtic boss Martin O'Neill has hit out at the poor sportsmanship of Uefa Cup final conquerors Porto.
O'Neill accused the Portuguese champions of blatant play-acting on their way to a 3-2 victory at the Estadio Olimpico.
However, he insisted Celtic would learn from the manner of their heart-breaking extra-time defeat and bounce back as a more potent European force.
"I will probably get into trouble for this, but it was poor sportsmanship," O'Neill said. "The rolling over, the time wasting.
"But they have beaten us, well done to them and it's up to us to learn from this.
"It is a steep learning curve, but this was a wonderful, wonderful experience.
Thompson could also have seen a second yellow card on two occasions
"The players put everything into it and the fans have been fantastic."
O'Neill's side twice came back from behind through goals from Henrik Larsson only for the sending off of Bobo Balde in extra time to turn the match once more in Porto's favour.
"We came roaring back every time they scored a goal and, if when we had 11 against 11 in extra time, I think we were the more mentally strong," said the Celtic boss.
"But it was not to be with Bobo getting sent off. It was a massive blow."
Porto coach Jose Mourinho hit back at any suggestion of underhand tactics, however.
"I'd prefer to ask whether the behaviour of the Celtic players was normal in your country," he said.
"What Balde did to Deco in front of me could have ended his career.
"The referee didn't affect the result, in that there were no doubtful decisions, but I think Balde could have had a direct red for his foul and Thompson could also have seen a second yellow card on two occasions.
"The referee wanted to end the game with 11 against 11 and I think maybe he was a bit afraid to send anyone off.
"There was a lot of commitment in Celtic's game, commitment, toughness and
aggression. I'm tempted to use another word - but I won't."
Porto could now go on and capture the domestic Double in Portugese football.
Mourinho said: "We have given a great example to the world and those who love
football and we have also made history by taking the Uefa Cup to Portugal for
the first time ever.
It was a bitter European experience for captain Paul Lambert, who failed to add the Uefa Cup to the Champions League winners' medal he won with Borussia Dortmund.
"I thought we were absolutely fantastic right through the game, but it was just one of those nights," he said.
Lambert was not prepared to echo the criticism of Porto, adding: "That is the way they play it. I thought they were great and deserved everything they got."