With the competition resuming after more than a month, both sides shook off early rust — and tough conditions — at Deakin Reserve to deliver a top contest for supporters starved of action.
But with momentum swinging Seymour's way just before the final break, it was the visitor which eventually reigned supreme in a 9.7 (61) to 4.9 (33) victory.
“They were down to 17 men either side of three-quarter time,” Seymour coach Ben Davey said.
“Jack O'Sullivan copped a hit that was probably a bit high and a bit late with about five minutes to go in the third, and we goaled from that 50m penalty and still had about 10 minutes in the last quarter with the numbers advantage.”
United had led by nine points at the first change and trailed by seven at half-time, but despite the dominance of Shane Neaves in the ruck could not impact the scoreboard in the second half — kicking 0.6.
Kier Bol, O'Sullivan and Mitch Waite starred for the Lions, as did Hudson Kaak, Lachie Waite and Ben Cooney (three goals).
“Kier's season has been fantastic,” Davey said.
“He's so solid in the backline and he's now not only keeping his man quiet, but he's helping out those around him as well.
“Jack really dragged us along and got us going in that third quarter and Mitch's stoppage work was great.
“Neaves is such a great ruckman and he was giving United first-use probably 80 per cent of the time around the ground. So Mitch's work in there was really crucial for us.”
Mitch Cleeland and Adam Fichera joined Neaves as United's best players, with Kyle Clarke, Jesse Cucinotta and Jack Norman also standing out.
“They really pushed us,” Davey said.
“They're really young, quick and skillful and they work really hard.
“It was one of those breezy Deakin days with the breeze going straight across the ground and not really favouring anyone, so it was a bit scratchy.
“But we're happy to get the four points.”
Senior debutant Shane Skidmore will await scans this week on his knee after going down with a knock for the Lions.
“Shane was our 11th debutant for the year which is great,” Davey said.
“We brought him along really slowly from a knee injury and he was ready to go, and you just really feel for him.
“It's a completely separate issue than the injury he was coming back from.”
More MMG sport
Tribunal news - Suspensions accepted, investigation opened
The News Award is back in business
It takes a village to raise three boys - and play 150 games of netball
Hats off to AFL Goulburn Murray for clothing donation
18°C