It was 43 minutes before Yeovil managed a shot at goal and it opened the scoring. They were awarded a free-kick 30 yards out and Lee Johnson blasted the ball into the roof of the net.
Earlier Yeovil had to be on their guard when Dean Gordon lined up free-kicks from distance for the visitors. In the 18th minute he fired just wide and eight minutes later a terrific shot from 30 yards out from the right hit the top of the bar.
Another Gordon free-kick on 34 minutes whistled past Chris Weale's right-hand post with the goalkeeper beaten.
Yeovil started the second half in a much brighter vein and in the 47th minute went two up. Phil Jevons, who was Grimsby's Player of the Year last season, started a move. Andrejs Stolcers got in the cross from the left and Bartosz Tarachulski met it with a firm header.
Grimsby kept pegging away but it was the 86th minutes before they got their consolation goal. They had replaced Ronnie Bull, who had loan spell with Yeovil last season with Ash Sestanovich and it was he who weaved his way cleverly through to plant the ball passed Weale.
Earlier Jevons had worked hard to try to add to his 14 goals to the season and appeared to have won a penalty but had claims turned down mid way through the half.
But Yeovil were pleased to hear the final whistle and can go into their final pre-Christmas match at Leyton Orient on the back of three straight wins.