Murphy reacted quickest from close range after Huddersfield's Anthony Gerrard miscued Aaron Cresswell's free-kick across his own six-yard area.
The Terriers took a 25th-minute lead through Danny Ward's clinical finish, after his strike partner James Vaughan saw a dismal penalty saved by Dean Gerken.
But Ipswich were level five minutes after the restart when David McGoldrick coolly struck his eighth of the season before Murphy's late winner.
McCarthy said: "Daryl Murphy was a real physical presence and had a couple of other chances beforehand. But like all centre forwards, he wants to score.
"Murphy and David McGoldrick are a good partnership, our best partnership. Diddsy (McGoldrick) is a more technical footballer, but Murphy is more powerful, aggressive and better in the air.
"If you could put them together, you would have one hell of a player - but then they wouldn't be here."
Summing up the game overall, McCarthy added: "I thought it was a great result and a fair one.
"It was a bit touch-and-go either way. I didn't think it was a penalty in the first half - so Vaughan got his just desserts.
"But we showed a great response to their goal and we have a great spirit at the club. People care about their mates, the team and the club."
Mark Robins was left despondent about the manner of the defeat, with the impressive Adam Hammill seeing a shot come back off the crossbar with the score at 1-0.
McCarthy admitted that was a turning point, while the Huddersfield boss was left to reflect on the positives of a run which has seen his side pick up three wins from four.
He said: "I can't be too critical of the lads. They tried to do things in the Huddersfield way and we have been competitive all season. They deserve enormous credit.
"Last season we were finding our feet, but it is different this year. It is clear we are not also-rans.
"The Championship is full of diverse teams who offer different things, but we coped with what Ipswich offered.
"We could have been 3-0 up at half-time and it wouldn't have been embarrassing.
"But we lost because we gave the ball away, the referee gave them two chances at the free-kick and we didn't pick them up."