Second half goals from Andy Carroll, Craig Bellamy and Dirk Kuyt completed a memorable seven days for the Reds after their Carling Cup and FA Cup triumphs over the two Manchester clubs.
But Wolves have now gone nine league games without a win - a run from which they have collected just four points - and there were boos at the final whistle.
McCarthy said: "After the last home game (against Aston Villa) there were huge rumours that I wouldn't be here.
"I can't imagine there will be any less after this game. We will see. I can hear what the fans are saying and I fully understand it. It was an unacceptable performance from us in the second half and watching that was unacceptable for me or anybody else.
"That's as bad a performance as we've had here or away. Fans pay good money to come and watch and they expect better and I understand that.
"If I had been watching, I'd have probably responded like that as well."
McCarthy added: "The lads are hurting, there are none of them that have come and not tried.
"But once we've conceded, we've gone on to be beaten by a considerably better side who have just beaten Manchester City and Manchester United.
"If you give them goals then it becomes hard work but I understand people's reactions."
The only consolation for McCarthy was the signing of Tottenham defender Sebastien Bassong on loan until the end of the season shortly before the transfer window closed.
There was no last minute deals by Liverpool boss Kenny Dalglish and Carroll scored his first league goal for three months after rumours circulated that he was surplus to requirements at Anfield.
Dalglish said: "We don't need to justify the rumours. That is not our problem.
"You must think we tell you lies because we came out and told you yesterday (Monday) there would be nothing happening.
"It's a wee but insulting when people don't believe you and I don't see why we need to be anything other than truthful.
"We were delighted with everyone who played and everyone made a contribution. It was great for Andy to score a goal. Craig scored a fantastic goal, as did Dirk."
Bellamy was the star of the show as he ran the Wolves defence ragged in addition to netting his ninth goal of the campaign.
Dalglish said: "Craig was fantastic again. I wish his numbers were the other way around that, instead of being 32, I wish he was 23.
"Craig doesn't do anything that surprises you. He prepares himself really well for matches.
"He knows the best thing for himself within the framework of the team. When he gets the ball, you are expecting something to happen."