The home side needed a late penalty from Nenad Milijas to force the game into extra-time. Then the arrival as substitutes of Kevin Doyle and Steven Fletcher provided Wolves with the firepower to seal a 4-2 success. Doyle netted a brace after setting up a goal for Fletcher to finally end the hopes of the League One side.
McCarthy said: "Notts County were excellent. They did to us what we did to Spurs for 75 minutes at the weekend. We get a penalty and then we go on and win. It seems a bit unjust on them but I felt the same way on Saturday. I was frustrated at times because our performance was very poor."
He added: "I am not undermining Notts County's performance. They played well and we weren't good enough to break them down until extra-time.
"But I was very disappointed. That was a Premier League squad, no trialists, no kids, nothing like that.
"Our team that played ought to be capable of playing better."
County played for the final 37 minutes with 10 men after defender Liam Chilvers was red carded when conceding the penalty converted by Milijas for a foul on Christophe Berra.
Manager Craig Short said: "I'm frustrated. You are winning and have the chance to make it two-nil and finish them off. But I'm exceptionally proud of them. They showed so much. They are so disappointed because it was there for the taking. There were some magnificent performances.
"They played with a lot of style at times, a lot of composure. I am frustrated."
Short also criticised the decision to yellow card striker Lee Hughes - the target of constant abuse from Wolves fans - after he had opened the scoring. Hughes wore a T-shirt underneath his club shirt displaying the words 'Boing, Boing' - the theme song of his former club West Brom.
Source: PA
Source: PA