Tonight's 3-0 victory over Cardiff moved his team into seventh in the Coca-Cola Championship - just two points behind Crystal Palace and three adrift of Watford with two games to play.
Ipswich's last-gasp equaliser at Molineux on Saturday may have taken Wanderers' fate out of their own hands, but in a division which has thrown up shocks week after week, McCarthy believes there could be a few twists and turns yet.
He said: "They can only give it away, they can only lose it now. They will be nervous.
"We could win both our games and still not get in there. But it's there for someone to throw it away, it's happened before and it could happen again.
"We cannot throw it away. We can only win our games and get in there but whether that makes it any easier for us to bear, I don't know."
He added: "The league is so topsy-turvy that I don't know what will happen come the last game of the season. Who's just above them? They might just be looking over their shoulders as well. I don't know.
"What if we (Wolves and Palace) both go and lose on Saturday? Let's try to win the game and then we will see. We will know a bit better after Saturday. I hope we still don't know anything and it's still on."
Andy Keogh's bullet header handed the home side an eighth-minute lead before Sylvan Ebanks-Blake served further notice of his growing reputation with his ninth goal in the last 11 games.
Wanderers picked up where they left off in the second half and Michael Kightly tapped in from close range in the 57th minute after City goalkeeper Peter Enckelman had spilled Ebanks-Blake's shot.
Yet despite the convincing scoreline, McCarthy felt his side performed better in their 1-1 draw with the Tractor Boys.
"We didn't play as well but we won. I don't know how you arrange that every week but if I could find the formula it would be great," he added.
A chest infection prevented Bluebirds boss Dave Jones taking his place on the bench, however there were few signs of a tonic in his side's display.
"He's not been well for about five or six days. He's had a chest infection, a bad throat and sounded awful," assistant boss Terry Burton revealed.
"He's kept battling it and kept fighting it. I think yesterday his temperature was up and he needed a couple of days away from it."
The FA Cup final is now all the Bluebirds have to look forward to after their play-off hopes were officially ended for another year.
But Burton denied suggestions the game may have been on his players' minds as they slipped to a second successive defeat.
"Of course it's there and you can't take that away," he said. "When the players go out on the pitch are they going out there and thinking of the FA Cup final?
"I would have to say no, they are thinking about what they would have to do to try to win that game.
"It just so happens the last two results haven't been particularly good ones for us. But listen, I hope it happens again next year."