Thistle played hosts to Stenhousemuir in the third round of the Scottish Cup at St Andrews University but were left reeling as they were torn apart by last season’s quarter finalists.
Thistle were undone after only six minutes when Ireland was turned inside out by Brown who picked out Kelso whose turn and shot was drilled low past Henderson.
After 27 minutes Stenhousemuir doubled their advantage when a long kick from keeper Weir was collected by Brown who showed great composure to fire into the net from the edge of the box.
Any chance of a comeback was all but undone with a calamitous goal minutes from the break when McLean shook off Shepherd but his ball into the box trickled along the ground however Henderson somehow missed the ball catching Gorgon out, who was behind the keeper, as he turned the ball into his own net.
Stenhousemuir made it 4-0 just two minutes after the restart when Brown fired home at the back post unmarked.
Thistle had a brief spell where they began to finally find a man with their passes and Weir produced a couple of decent stops to deny Barnes then Petrie who were starved of supply for most of the game.
Goal number five arrivedbut it was harsh on Thistle who had clearly played Kelso offside, however the referee waved play on and the striker fired home.
Stewart wrapped up the scoring.
Alba Mortgage Solutions man of the match – Ryan Thomson.
Thistle – Henderson, Ireland (Foulkes 56), Gorgon, Carson (Capt), Thomson, Shepherd (Wright 62), McArthur, Cameron (McShane 56), Jukes, Barnes, Petrie (Harrow 56).
Sub not used – Addison.
Tomorrow (Saturday) Thistle have a free week.