Jordy Mongoy stepped off the bench to head in a priceless winner for South Shields at Belper Town on Saturday.
The game was poised at 0-0 until Mongoy's vital intervention 10 minutes from the end in Derbyshire.
The result extended Shields' unbeaten record to eight games as they stretched their lead at the top of the Pitching In Northern Premier League to nine points.
There are now 11 matches remaining for Kevin Phillips' side, but they were made to work for their latest victory by a spirited Belper side battling the prospect of relegation.
Shields suffered an early blow when Dillon Morse was forced off injured within the first 10 minutes. Morse himself was a replacement for Tom Broadbent, who had been ruled out with a calf injury.
That did not stop the Mariners recording their 16th clean sheet of the season in all competition, and it was on that base the win was founded on.
The game's first attempt on goal came from Mackenzie Heaney, whose strike from 20 yards was well saved by Tom Jackson in the Belper goal after good work from Darius Osei and Dylan Mottley-Henry.
Midway through the first half, Shields went closer when Osei's effort clipped the outside of the post after more impressive build-up play.
It felt as though the visitors were gathering momentum, but Belper fired them a warning as Ben Rhodes played in Rio Molyneaux and he could only fire wide when well placed.
Shields were on top in the possession and territory stakes but a breakthrough was difficult to come by, and they needed Myles Boney to save from Molyneaux at the other end to keep the score level heading into half-time.
The Mariners started the second half full of purpose but continued to find Belper difficult to break down, with Martin Smith and Heaney both trying their luck from distance to no avail.
Mongoy was introduced to the action with 17 minutes remaining and his impact was instant, forcing Jackson into a smart save.
He then left the goalkeeper with no chance as he headed in the crucial goal, sending the ball into the bottom corner after a brilliant cross from the right by Jordan Hunter.
Shields were impressive as they saw the remainder of the game out to return to South Tyneside with a crucial three points.
They are back in action on Saturday when they travel to Marske United.
South Shields: Boney, Hunter, Adams (c), Liddle, Morse (Doherty 8), Smith, Heaney, Briggs, Osei, Alessandra (Gomes 73), Mottley-Henry (Mongoy 73). Subs not used: Shokunbi, Woods.
Goal: Mongoy (80).
Attendance: 701.
Image: Kev Wilson.