The home side were clearly fired up for the match, knowing that the three points would make them the 2014-15 Toolstation NCEL Premier Division Champions and the Ducks duly wrapped up the title by racing into a 3-0 half time lead with goals by Danny Frost, Lee Morris and Andrew Fox.
Cleethorpes created very little in the first period, finding themselves very much under the cosh, but did come close when Marc Cooper's snap shot after a blocked free kick flashed just wide before Robertson was denied by a world class save by Ducks goalkeeper Ian Deakin.
The visiting Owls improved after the break with Cooper hitting the post from the restart but had to wait until the last minute to get on the scoresheet as Robertson finished with a lovely flick into the top corner