McCarthy has attempted to rejuvenate his side for their second season back in the top division by bringing in four new players.
Steven Fletcher's debut goal gave an instant return on the reported £6.5million spent to recruit him from Burnley while Jelle van Damme also shone on his first appearance.
Their other high-profile new signing, Stephen Hunt, did not feature due to injury.
McCarthy said: "I'm very pleased with them both, I thought the two lads were great.
"We played well today, we had a good spell - Kenwyne Jones went off, maybe that threw them a bit out of kilter.
"We had our best spell on the back of that.
"It turned out not to be a convincing win but it was a convincing performance.
"I'm a bit disappointed we conceded one, we made a little mistake there."