Graeme High School kicked-off the second half confidently with their 1-0 lead, as Jack Hodge and Fotheringham shared some lovely one-two passing on the right wing in the 50th minute, before an opening lead to a shot from Romanis, which was well saved by Matthews.
St. John's perseverance soon caused a stir in the 60th minute, as quick feet from Cameron Ross and Cameron continuously pressured the Graeme defence, which received encouragement from their support.
The final ten minutes had both teams having all to play for, while Cameron continued to trouble the Graeme defence with an effort soaring just wide in the 83rd minute, Graeme's Romanis continued to fire balls into the box in the hope that it may break for one of his teammates.
It was the determination of St. John's which gave them the edge needed to seal them the victory as the 90th minute approached, when McGrath caught the ball in the box, setting it up for himself with his first touch and firing it into the back of the net with his second, which resulted in a famous Hampden roar from the crowd.
However, St. John's ruthless attack didn't settle as the game entered extra time, with a lovely turn from Meekison in the final third putting him into space to set up Cameron, who's perseverance finally paid off with a goal.
Cameron sent the ball soaring across the front of Sandberg and into the far side of the net, bringing the scoreline to 3-1.
The Hampden crowd continued to be treated to the sight of goals in extra time, as Hodge sent a free kick straight into the penalty area from just in front of the half-way line, where it bounced and broke for Ryan Fleming who calmly placed the ball into the net and earned Graeme High School a consolation goal at 3-2.
Graeme's defence continued to work exceptionally hard in an attempt to keep St. John's at bay throughout the match, especially Kyle Ewing, who's series of crunching tackles caused frustration amongst the St. John's attack.
While both teams fought hard throughout the fixture, with both having a series of close chances, it was the excellence of St. John's finishing in the final third which clinched them Cup Final glory.