Frimpong, who was on loan at Wolves from Spurs' local rivals Arsenal, was the target for jeers from the crowd during Saturday's 1-1 stalemate.
He was substituted midway through the second half by McCarthy, but the Wolves boss was pleased with the midfielder's display at White Hart Lane.
"I thought he was so unlucky with the free-kick he gave away because I thought he won the ball with a good tackle and it was a poor decision," said McCarthy.
"I took him off because he might have got a second booking.
"I said to him at half-time that if he got warned for another one I might have to take him off.
"I'm sure Spurs would have loved to have been playing against ten men and I wasn't going to let that happen. For safety's sake I took him off.
"I've been there as a young player when you're coming off and 30 or 40 thousand are giving you dog's abuse.
"And you have to smile and have a sharpened pencil between your teeth and just take it.
"And he was fine - he was really, really good. He put in a mature performance and I was really pleased with him."
