The Sir Bobby Robson National Football Day saw former Ipswich players paraded around Portman Road before a comfortable 3-0 win over a Millwall side still searching for their first league points.
When asked what Sir Bobby would have thought of the result, McCarthy said: "I think Sir Bobby might have liked a bit more silky football to be honest. I still think he would have taken a 3-0 win, however it came.
"As a manager, you can't always win playing free-flowing football. I think he would have been happy enough with that."
A typically honest McCarthy felt the margin of the victory flattered his side as two own goals from Shane Lowry and Mark Beevers sandwiched a fine header from Town centre-back Tommy Smith.
The Blues boss said: "I think we edged it - I don't think there would be any doubt in that. It was a solid performance though 3-0 probably put a gloss on it."
After Lowry's unfortunate own goal, Smith's header in the 70th minute largely made the points safe and had his manager purring.
McCarthy joked: "Of my 12 in my 500-odd league games, they were genuinely all like that - I can remember most of them. It was a magnificent header."
Millwall's fate was sealed in the 82nd minute when Beevers deflected Paul Anderson's header past stranded keeper Stephen Bywater.
While McCarthy has got Ipswich's infant season back on track, following an early Capital One Cup exit at the hands of lower-league Stevenage, Millwall manager Steve Lomas sees his side as a work in progress.
The Lions boss admitted: "The first goal was a mistake from our point of view. It was a really poor, soft goal, pretty much out of nothing.
"Once you concede one, especially away from home, you have to keep going and keep it at one-nil for as long as possible.
"But we didn't give ourselves a chance to get back in the game. The second goal was a needless free kick out wide and a free header inside our box."
Trying to remain positive at the task ahead, Lomas added: "It is not the end of the world, but we are disappointed. We knew Ipswich were going to come out of the traps, at home on Sir Bobby Robson Day and after two defeats.
"Our target was to at least get to half time with a clean sheet, which we did. We started the second half on the front-foot with a couple of chances - Chaps (Richard Chaplow) at the front post and maybe James Henry had a shout for a penalty. But once it goes to 2-0, the game is normally dead and buried."