Southend extended their unbeaten run in the Vanarama National League to 13 games with a 1-0 win over Grimsby at Roots Hall.
There was little to choose between the teams during the first half, with Harrison Neal seeing his long-range shot pushed over by Grimsby keeper Max Crocombe.
The Shrimpers broke the deadlock just after the hour when Callum Powell was fouled in the penalty area and Sam Dalby slotted in his 10th goal of the campaign from the spot.
The Mariners had five wins from their last six games but could not conjure an equaliser, with forward John McAtee dragging an effort just wide.