AN 86TH-MINUTE penalty settled this hard-fought local Uni-Bond Premier Leaguederby in favour of the Motormen, who now seem certain to qualify for Conference North football.
The defeat leaves Marine almost certainly chasing a play-off place as their recent unbeaten sequence came to an end.
The visitors had the ball in the net after 12 minutes when McNally converted Connolly's header from the far post, but an assistant's raised flag disallowed the effort for offside.
At the other end, Fearns went close and Spellman had a shot blocked before a nasty clash of heads saw both Marine's Mullin and Vauxhall's Tomlinson immediately substituted, the latter requiring hospital treatment.
Fearns went close again after the break, before Marine raised their game in which Kay had one shot blocked after a great pull-back by Young and another effort went well over the bar.
Crookes then denied Cumiskey with a fingertip save before Black was thwarted by Dittmer at the opposite end.
Then on 85 minutes a great pass by Motors' Roberts ena-bled Cumiskey to attack the Marine defence and his fierce drive struck the face of the far post.
But the danger was not over and as Fearns wriggled his way back into the box, his legs were removed and the referee pointed to the spot.
The Vauxhall striker then dusted himself down to convert his third penalty in as many games for his 37th goal of the campaign as the Motor-men extended their unbeaten run to 11 matches.
VAUXHALL: Dittmer, Spellman, McDermott, Robinson, Roberts, Lynch, Nesbitt, Lawton, Fearns, Tomlinson, Cumiskey. Subs: Macauley, Parry, Griffiths.
MARINE: Crookes, Murphy, Mullin, Kay, Connolly, McNally, Dolan, Ellison, Taylor, Young, Culshaw. Subs: Thurston, Townsend, Black.