Blackburn boss Sam Allardyce claimed referee Howard Webb was wrong to send off El Hadji Diouf during Saturday's 3-1 FA Cup third-round defeat to Aston Villa.
The Senegal forward was shown a straight red card for a first-half tackle on Villa defender Habib Beye.
Rovers were trailing 2-0 at the time and even a second-half reply from Nikola Kalinic failed to inspire a fightback.
"I see a lot of those situations that never result in a sending-off," claimed Allardyce.
"They will justify it by saying it was two-footed but the referee, Howard Webb, is a long way away.
"He did not know what sort of tackle it was because I have seen a playback on the video. If the assistant referee made the decision, then fine, but I don't think he did."
Speaking about the cup exit, he added:"I have to give them great credit for the way they played in the second half, but all the damage was done in the first half for us.
"We gave ourselves such an uphill battle as the first half was a disaster. We went 2-0 down, missed a penalty and had a player sent off.
"At least we showed the right professional approach in the second half to get back into the game, even with ten men."