The Brazilian midfielder was cautioned by referee Andre Marriner in the second half of the Blues' 2-0 FA Cup third round win at Derby County after the match official awarded the same player a penalty for a fall against West Bromwich Albion in the Premier League in November.
The incident comes after Oscar was booked for diving at Southampton on Wednesday but Mourinho maintains his side's innocence.
"I maintain (there are no divers at Chelsea). Isolated episodes. The referees attacking it. The manager supporting the referees. I think we are doing well. Let's see if the others do the same as us," he said after the win at iPro Stadium.
"Marriner was so close so if he made that decision it's because he's right.
"The last time Oscar's justification was completely correct and I understand completely what happened.
"I was happy with the card because the referee, in this case (Martin) Atkinson, did well.
"This time I didn't speak yet with Ramires, but if the referee was there and he decide well, perfect. Let's do every game, every stadium, every player, let's do that."
He added: "In other clubs there are really (sic) divers and they are not booked.
"Players are doing that every weekend. Sit in front of the television and you will find them."
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