Newcastle United Women 2 Portsmouth Women 1
Newcastle United Women booked their spot in the FA Women's National League Cup final thanks to a 90th-minute strike from Georgia Gibson in front of the Gallowgate End.
United took the lead through Charlotte Potts, who headed into the far corner, but Portsmouth rallied and got back on level terms through Emma Jones when she dinked the ball over a sliding Grace Donnelly.
Just as the fourth official held up seven minutes added on, Katie Barker picked out an unmarked Gibson, who got a deft touch on the ball to guide it into the far corner and send another big St. James' crowd wild.
It was a close contest with both side showing off their quality and trading blows in front of a bumper 22,307-strong attendance, but it was United who came out victorious.
There was an early scare for Newcastle when a mix-up at the back allowed Jones to sprint through on goal but Donnelly was quick off her line to thwart the danger.
Gibson thought she'd added to her St. James' Park tally of three in her previous three games at the ground when she leapt above the Portsmouth defenders to meet an Emma Kelly free-kick but could only guide her header over the bar.
Minutes later Newcastle had another chance from a set piece. Tyler Dodds fizzed in a dangerous corner but Potts' header narrowly missed the far post with many thinking it had crept in.
Portsmouth were struggling to cope with United's set pieces as Potts connected well with a Dodds corner, but Hannah Haughton pulled off a stunning save from point-blank range to keep the visitors level.
In what was a tightly-contested first half, Portsmouth almost took the lead just before the break. Pompey worked the ball well on the edge of United's box before Georgie Freeland fired a vicious effort, forcing Donnelly to tip the strike over the bar.
United came out roaring in the second half and were almost rewarded with a dream start when Jasmine McQuade showed great composure in the Portsmouth box to take a touch and fire goalwards.
Haughton pulled off a superb fingertip save to push the ball onto the crossbar with the Gallowgate End on their feet.
Moments afterwards, the fans inside St. James' Park were jubilant as Potts headed home from a deep Dodds cross. After coming close on two occasions in the first half, the defender made no mistake in finding the back of the net.
Despite not threatening the United goal much in the second half, Portsmouth found themselves level against the run of play when Jones raced in behind to slot beyond Donnelly.
United continued to look the brighter side after the equaliser when a ball was cut back to number nine Barker but she could only watch on as her effort bounced back out off the crossbar.
Moments later Paige Bailey-Gayle looked set to put United ahead as she turned excellently in the box, only for Dani Lane to block her effort with an outstretched arm, allowing Haughton to collect the ball.
Newcastle were not letting up and continued to pepper the Pompey goal, with the visitors once again seeing the woodwork come to their rescue when Bailey-Gayle's deflected effort looped over Haughton and bounced off the bar.
The Lasses kept knocking on the Portsmouth door and their pressure finally paid off when Gibson found herself unmarked in the box and glanced a delightful header past the stranded Haughton.
United never gave up and fully deserved their dramatic winner, with Gibson and the rest of the Newcastle squad lapping up their applause from a jubilant Gallowgate End.
Newcastle United Women: Grace Donnelly, Lia Cataldo, Charlotte Potts, Hannah Greenwood, Katie Barker, Emma Kelly, Amber-Keegan Stobbs, Jasmine McQuade, Georgia Gibson, Tyler Dodds (Kacie Elson 85), Paige Bailey-Gayle (Bridget Galloway 90+2)
Subs not used: Anna Soulsby, Sharna Wilkinson
Report by Aaron Hindhaugh