Thistle travelled to Quarry Park to face current Wallace Wright Cup holders Leslie Hearts in the semi-final of the competition.
They got off to a great start and opened the scoring when Petrie and Barnes combined to good effect before the latter put the ball across the face of goal for the ever alert Ireland to fire home.
After 14 minutes it was 2-0 to Thistle when Petrie sent Barnes through on goal with a perfectly weighted pass and Thistles top scorer didn’t disappoint as he slotted the ball past Ireland.
Thistle dominated the early exchanges but took their foot off the gas as the half progressed.
But they netted a third goal before the break when Barnes curled a fantastic free kick into the top corner.
The second half was barely two minutes old when the hosts grabbed a lifeline through Neil who fired home a cross from close range.
Thistle restored their three goal advantage when Jukes showed some neat skill to lift the ball over the advancing keeper and into the net.
Leslie weren’t done yet though and continued to battle away and indeed only a great save from Anderson denied Porter from a free kick.
With 65 minutes gone Leslie kept their interest in the match as they pulled back a second goal.
With six minutes to go Thistle killed off the resolve of Hearts with a fifth goal when Barnes made no mistake to grab his hat-trick and send his side into the final.
Golf City Taxis Man of the Match – Roland Harrow.
Thistle – Anderson, Ireland (McShane 80), Carson, McArthur, Dunn (Caithness 63), Jukes, Gorgon, Thomson, Harrow (Cameron 84), Barnes, Petrie (Malone 56)
Sub – Ross.
The final will be played tonight on Friday, May 5 with a 6.30pm kick off against Burntisland United at Moorside Park, home of Dundonald Bluebell. All fans welcome.