The Yellows prevailed 6-5 on penalties away at South Shields, with goalkeeper Dan Atherton the hero, saving two in the shootout.
Darius Osei had earlier given Shields a first half lead, only for Jordan Buckley’s equaliser to force extra time in a thrilling semi-final.
That result meant that Scarborough Athletic will host the play-off final, following their 2-1 win over Matlock Town.
An equal-high NPL crowd of the season of 2,676 saw goals in the final quarter from Ashley Jackson and Luca Colville put the Seadogs in front, before Liam Hughes pulled a late goal back.
In the Midlands and West Divisions, the play-off finals will be contested by the teams finishing 4th and 5th in the table in dramatic circumstances.
Chasetown won away at Halesowen Town thanks to Jack Langston’s injury time penalty, and in the other game, Belper Town shocked second place 2-1 Stamford with Kyle Dixon striking an injury time winner moments after Cosmos Matwasa had equalised.
There was late drama in the West Division too, as Marine completed a comeback from 2-0 down at Workington with Neil Kengni’s goal deep in to injury time.
Kengni went on to score the winner, and secure his hat-trick, as Marine won 3-2 after extra time.
They will travel to Runcorn Linnets for Saturday’s final after a blistering start fired Linnets to victory at Leek Town.
Iwan Murray and Ryan Brooke fired Runcorn in to a 2-0 goal lead inside the first four minutes, and Thomas Lloyd Marsh-Hughes made it three by half time.
Although Tim Grice pulled a goal back, Ryan Brooke made sure for Calum McIntyre’s side.
In the East Division, Marske United needed extra time to see off Shildon 2-1.
Adam Boyes fired them in to a 77th minute lead, but Dean Thexton forced extra time with an 81st minute equaliser. Jason Kennedy struck the decisive goal in the 113th minute.
Marske, the only side to have finished second in their respective division and reach the final, will host Stockton Town.
Stockton were 2-1 winners away at Cleethorpes Town, with all three goals coming in the first half.
Saturday 30 April
East Division: Marske United v Stockton Town
Midlands Division: Chasetown v Belper Town
West Division: Runcorn Linnets v Marine
Monday 2 May
Premier Division: Scarborough Athletic v Warrington Town
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