A solitary strike from Ally Waddecar ensured Bamber Bridge will take a place in the play-off final.
They will meet the winners of Darlington 1883 and Ramsbottom United after a perfect second-half display from Neil Crowe’s men, who dominated their opponents with quick attacking football.
A quick start at Cantilever Park saw Warrington winger Scott Metcalfe volley wide of goal inside a minute before tricky winger Waddecar saw his cross from inside the area cleared.
Metcalfe then registered the first shot on target after five minutes firing straight at Lee Dovey from 20 yards.
Warrington’s Ben Wharton then volleyed over from eight yards and then Brig had their best chance as Curtis Thompson crossed low in the area and target man Greg Johnstone had a shot blocked on the line.
Wharton was involved in the action was again midway through the first half but he skewed a shot wide of goal from 10 yards.
It was end-to-end stuff as both sides went in search of that all-important first goal.
Carlos Meakin saw a goalbound volley deflected wide by George Bowyer while at the other end Brig’s Waddecar was constantly getting in behind Warrington full-back David Thompson.
As the first half neared to a close, the game turned scrappy, Warrington committing a number of cynical fouls but referee Andrew Cawtherley opted to keep his cards in his pockets.
Minutes before the interval, Brig goalkeeper Dovey then produced an excellent save diving to his right to deny the impressive Metcalfe.
Just three minutes after the half-time whistle smart work from Waddecar saw Brig take the lead.
As the ball bounced in the Warrington area, it fell to front man Waddecar who jinked his way past two defenders and fired past Ollerenshaw.
Brig missed a chance to double their lead just after the hour mark – after Waddecar was hauled down in the area, Johnstone stepped up but goalkeeper Ollerenshaw saved well diving to his right.
As the game entered its final stages, the home side grew frustrated and full-back Thompson was sent off for a second bookable offence after lunging in on Waddecar.
Brig defended superbly in the closing seconds to seal a place in the play-off final.
Warrington Town: 0
Bamber Bridge: 1
Bamber Bridge: Dovey, Bowyer, Alexander, Lawlor, Doughty, Kay (c), Waddecar, Thompson, Johnstone, Taylor, Marlow Subs not used: Williams, Reid, Watt, Buchan, Reynolds.