South Shields sealed promotion to National League North with two games to spare as Tom Broadbent's header saw off the challenge of Whitby Town in a tight encounter.
The Mariners went into the game knowing maximum points would secure the Pitching In Northern Premier League title, but they were provided with a stern test by the seaside.
Myles Boney was called upon to keep the hosts at bay before Broadbent nodded his side in front 10 minutes before half-time to send them on course.
A controlled second half performance saw the game out as the Mariners climbed to the sixth tier for the first time since the club's reformation in 1974.
Shields showed few signs of nerves at the outset and made an enterprising start, with Robert Briggs guiding their first attempt at goal wide of the target after a cross from Jordan Hunter.
Heavy rain early in the afternoon resulted in a heavy playing surface, and that played a role when the Mariners almost took the lead in the 10th minute.
Hunter got in down the right of the box and his drilled delivery was kicked by Whitby goalkeeper Shane Bland to Dylan Mottley-Henry, whose header into the ground became caught up in the pitch, which allowed a defender to clear.
Whitby almost caught Shields out at the other end when Harry Green was played in on goal, but Boney was alert to the danger and rushed out to tackle the forward before saving from Bradley Fewster.
Boney then made an excellent stop with his legs to deny Green after he was found on the left of the area.
The game was beginning to open up and the Mariners were next to go close, Briggs firing narrowly wide from the edge of the box after a lay-off from Mottley-Henry.
Shields again needed Boney to save with his feet when Green slipped in Aaron Haswell down the left and his powerful strike was destined for the bottom corner.
Those saves reaped further rewards 10 minutes before half-time when the visitors broke the deadlock.
Martin Smith curled in a superb free-kick from the left and it was met by a towering header from Broadbent, who sent the ball into the opposite corner and the big travelling support into raptures.
Whitby could have levelled as the first half ticked into stoppage time when Green again burst through on the left, but his deflected strike went narrowly past the upright.
The second half was a more sedate affair, with no clear-cut chances created at either end, which suited the Mariners just fine on what proved to be a historic afternoon.
Shields can now savour Saturday's final home game of the season, against Warrington Town, with their status as champions secure.
South Shields: Boney, Hunter, Adams (c), Liddle, Broadbent, Smith, Heaney (Morse 77), Newton, Alessandra, Briggs (Mongoy 56), Mottley-Henry (Osei 46). Subs not used: Gomes, Gardiner.
Goals: Broadbent (35).
Image: Kev Wilson.