Referee Claus Bo Larsen has revealed Chelsea secretary David Barnard told him they did not want to see certain players booked ahead of their clash with Liverpool.
The Blues travelled to Anfield on Wednesday for the first leg of their quarter-final clash with John Terry, Ashley Cole and Nicolas Anelka one yellow card away from missing the second leg.
Guus Hiddink's side triumphed 3-1 at Anfield to move to within touching distance of the semi-finals, but will be without skipper Terry at Stamford Bridge after he was cautioned during the game.
And Bo Larsen has admitted he was taken aback by a comment from Barnard before the match.
"I've never experienced anything like this," the Danish official told BT.
"When we had a safety meeting on Wednesday morning, a representative from Chelsea said, 'Claus Bo, you should just remember that we have some players who have a yellow card already and we are not so excited if they get one again'."
The organisational meeting is standard procedure and was also attended by Liverpool secretary Ian Sylvester, Barnard, Merseyside Police and the UEFA match delegate.
"We were quite shocked," added Bo Larsen. "I have been to more than 100 safety meetings and this is the first time I experienced such a thing.
"It was while Liverpool and UEFA and other people were there. I responded by saying that if a player does something for a yellow card, he gets a yellow card."
Chelsea have insisted they had every right to raise the issue of players on yellow cards.
The Blues issued a statement in which they said the meeting was an appropriate moment to point out that a number of players, including two from Liverpool, were one booking away from a ban.
A spokesman for Chelsea said: "UEFA organisational meetings are opportunities for all parties to raise valid issues in relation to that day's game.
"Therefore, it was an appropriate meeting in which to raise the issue of both teams fielding players on yellow cards.
"Chelsea did not raise the issue solely in relation to Chelsea players."
Liverpool's Alvaro Arbeloa and Andrea Dossena were also walking a disciplinary tightrope ahead of the game but neither were cautioned.