Blackburn will face Chelsea at Stamford Bridge today.
McCarthy told The Sun: “Any match against Chelsea is always difficult but we are capable of springing a surprise this season.
“I’ve warned their defenders me and Santa Cruz can create plenty of problems in their penalty area.
“They are coming into the match after a defeat against Aston Villa and that could affect their morale. So that could be a little advantage.
“It’s always special because it is the team of my old friend Mourinho.
“But this day that friendship is forgotten and I only want to win and make him suffer — then after the match it will be back to normal.”