John Hartson delivered a harsh verdict on youngster Hayden Muller after he gifted Rangers the platform to stage a McDiarmid Park comeback.
The former Celtic striker told the 19-year-old Millwall loanee 'this is why you're at St Johnstone ' in a scathing on-air snipe at his tackle on Ryan Kent.
Muller brought the winger down in the box with a sliding challenge that allowed Kemar Roofe to step up and cancel out Michael O'Halloran's opener for Saints.
James Tavernier then smashed in a stunner to win it for Steven Gerrard's side but Hartson reckons Muller's foul was the turning point.
He told Go Radio: "St Johnstone go 1-0 up with a decent goal and then the boy Muller...
"You think to yourself 'this is why you're at St Johnstone, by the way, no disrespect, because you do reckless and stupid things'.
"Why go and tackle? Why go on your backside and slide tackle in the box? He brings down Ryan Kent when he's going absolutely nowhere.
"You give a penalty away and allow Rangers to come back into the game. Not using your head, not using your savvy, not using your football intelligence.
"Then, in all fairness, Tavernier scores a goal worthy of winning any game and they go on and win it."
Muller joined last season's Scottish Cup and Betfred Cup winners on a season long loan back in July.
