Wolves picked up seven points from the opening three games in the Barclays Premier League but have since suffered a trio of successive setbacks.
McCarthy is looking to bury the memory of a woeful 3-0 reversal against QPR in their last home meeting a fortnight ago but knows his players will have to be at their best against unbeaten Newcastle.
The Wolves boss said: "We've had one bad performance against QPR. We were below our standards. Other than that, we've played well.
"When we had our good start, two wins and a draw, I didn't get carried away with it because I can almost see what is coming around the corner if you are not careful.
"No-one could say we were complacent because that is never going to happen.
"We lost to a really good Spurs side at home having played well for 65 minutes and go to Liverpool and play well against a strike force that cost ?70 million.
"When you get beat it is not always because you play badly but against QPR in our last home game wasn't our standard. That was the real one that has let us down. I was as dumbfounded as everyone else.
"It would be a huge boost to get a result before the internationals. We need to stop that run of defeats. We don't want to be going into the break with four defeats on the bounce."
McCarthy believes Newcastle have become "a better unit" after the departure of Andy Carroll, Joey Barton, Kevin Nolan and Jose Enrique since last January.
He said: "As a manager, if you lose people who go and sign for someone else, the first question is 'what have you got?'
"Generally the answer the managers give is we've got the players who will have to step up - and that is just what has happened at Newcastle.
"They lost some big players and big characters out of their team and maybe it's been a good thing for them, I don't know.
"But they seem to have been galvanised and become a better unit for it. They are at the moment. They are playing well.
"Demba Ba scored a hat-trick last week so I'm sure he will come down here feeling good about himself and Leon Best has had a good start to the season.
"They also have two good wingers in Jonas Gutierrez and Gabriel Obertan. That's enough to start with!"
Wolves striker Kevin Doyle will be looking to make his mark after signing a new four-year contract and McCarthy was convinced he would not leave Molineux despite constant speculation.
McCarthy said: "I'm delighted we've resigned Kevin and it shows we are serious in our ambitious about what we want to do.
"In the summer when everyone was asking me if he was going here, there and everywhere, I said 'I don't think so, he is staying here'.
"I'd be a liar if Manchester Utd or Arsenal came in and bid for him and wanted to pay us a whole load of money, and Kevin thought he could play in the Champions League.
"He is ambitious, of course, but he has never indicated he wants to go anywhere else. He loves it here and we love having him around."
Source: Team Talk
Source: Team Talk