Player-manager Paul Groves led by example and netted the only goal just after the hour to give struggling Grimsby a timely boost against FA Cup semi-finalists Watford.

John Oster, on loan from Premiership strugglers Sunderland, crossed from the right and Groves expertly back-heeled the ball home from six yards.

It was just reward for the Mariners, who soaked up early pressure from Ray Lewington's side to more than match their opponents for the remainder of the match.

They were certainly the better side after the interval and Groves' vital strike moves them off the foot of the table. Up until his goal, however, chances had been at a premium with Watford's Heidar Helguson guilty of missing the best of them.

Watford, desperate to reproduce their outstanding FA Cup form to boost a stuttering league campaign, failed to maintain their momentum as the home side's confidence grew.

The visitors won an early corner before Gavin Mahon tested Danny Coyne in the Grimsby goal with a close-range shot.

Stuart Campbell carved out Grimsby's first opportunity, his effort from 20 yards comfortably saved by Alec Chamberlain after seven minutes.

But it was Watford who continued to looked the more threatening early on with Helguson sending a long-range effort over the crossbar as they continued to press.

The home side, though, worked their way into the game and continued to try their luck from distance with Chamberlain again called into action to save Darren Mansaram's 25-yard strike.

Watford went close again after 16 minutes when Tommy Smith's cross found Helguson in the area, but he sent his shot wide of the target from six yards. It proved a costly miss.

Teams

Grimsby: Coyne, McDermott, Ford, Santos, Gallimore, Oster, Pouton (Barnard 30), Groves, Richard Hughes, Campbell, Mansaram.

Subs Not Used: Allaway, Chettle, Livingstone, Soames.

Goals: Groves 64.

Watford: Chamberlain, Ardley, Cox, Gayle, Robinson, Hand (Noel-Williams 69), Hyde, Mahon, Glass (Vernazza 81), Helguson, Tommy Smith (Dyche 81).

Subs Not Used: Brown, Lee.

Booked: Robinson.

Att: 4,847

Ref: P Prosser (Gloucestershire).