Danish referee Claus Bo Larsen insists he was right to show Chelsea's John Terry a yellow card on Wednesday night.
The booking, picked up during the Blues' 3-1 victory over Liverpool in the UEFA Champions League, will rule the centre-half out of the second leg of the quarter-final tie.
The England skipper has questioned the decision, believing he had every
right to challenge for the ball in a tangle with Reds keeper Jose Reina.
However, having lunged in slightly on the Spanish shot-stopper, Larsen believes he was left with no option but to caution Terry.
"Of course he is a little bit bitter, since he will miss the return game, but he could have avoided running into the keeper on purpose," the match official told Bold.dk.
"This was purely calculated and I have no doubts this was the right decision."