The Cats were classy with ball in hand and put United to the sword with an eight-goal opening term at Deakin Reserve.
Leading goal-kicker Chris Nield starred with six goals, while mid-season recruit Jackson Trengove booted four goals.
The 87-point round 14 rout sees the Cats hold on to fourth spot on the Goulburn Valley League ladder.
Mooroopna managed to chalk up 18 inside 50 deliveries to seven and used the ball at 77 per cent efficiency by foot which pleased Cats coach John Lamont.
“We had a real focus to start well and stay on track for the rest of the game ... we came away very pleased,” Lamont said post the 18.13 (121) to 5.4 (34) triumph.
“We wanted to be efficient with our foot skills and we did that. We didn’t want to over-use the ball which, as a young group, is something that we’ve worked on.
“I thought the first quarter was solid in that regard. Our young players continue to take steps forward which is pleasing.
“It was week two of our new dynamic in attack with Chris and Jackson and it’s always challenging to adapt mid-season but they both did well and had eight or nine shots on goal each.”
It was one of Mooroopna’s talented and versatile options who enjoyed a stellar day in the win.
Keelin Betson was rock solid in defence for the Cats, as he performed a relatively unusual rotation from defence to ruck.
Betson shined with 32 disposals, eight marks — five of those intercepts — six spoils and four rebound 50s.
United’s Liam Serra (30 disposals) and Kyle Clarke (27) both flew the flag for the home side.
Lamont praised the efforts of Betson.
“Keelin had an unusual rotation where he played down back and through the ruck,” he said.
“He grew up as a defender but with our match-ups he played as a defender and he was heavily involved all game which was very pleasing to see.”
Unfortunately for the Cats, onballer Kai Madgwick and Mitch Jones suffered injuries and will be in doubt for next week’s game for against Seymour.