Seymour gave up a slim first-quarter lead to lose to Mansfield by 13 points.
The Lions led by three points at the first break, largely thanks to a wayward kicking Mansfield which struggled to find its scoring boots.
They eventually did and the Eagles edged ahead in the second.
A disappointing third quarter saw Seymour fail to register a score while Mansfield extended its lead out to 23 points.
The Lions were more dominant in the final term, kicking three goals to the Eagles’ one, but their last-quarter efforts weren’t enough to reel in the home side.
Score: Mansfield 5.14 (44) d Seymour 5.1 (31).
Goals: B. Tarran 4; H. McLean.
Best: B. Tarran, J. Zuccala, J. Morgan, B. Le Cerf, D. McLarty, H. McLean.
Both Seymour and Mansfield were eager to get out of the blocks on Saturday, but a first quarter false start saw both sides kept to a zero score at the first change.
The Lions were first to build a lead, kicking four goals to six in the second term.
Their 11-point lead quickly blew out to 32 points thanks to a fruitful third quarter.
Seymour failed to register a major in the final quarter but the Eagles couldn’t muster enough for a come back, giving the Lions a 21-point win.
Score: Mansfield 6.2 (38) lt Seymour 8.11 (59).
Goals: M. Itter 3; W. Eager, K. Grant, D. Fisher, N. Davey, D. Cook.
Best: K. Grant, D. Cook, S. Voogt, M. Quine, S. Durham, W. Eager.