St Johnstone look to have ended the Dundee United career of manager Jackie McNamara after staging a remarkable comeback to win 2-1, despite playing most of the match with 10 men.
Saints had goalkeeper Alan Mannus sent off in the 22nd minute after conceding the penalty from which United took the lead.
But the Perth outfit roared back from Billy McKay’s spot-kick with two second-half goals that consigned United to a sixth defeat in nine Ladbrokes Premiership outings.
Graham Cummins equalised with a 64th-minute header and substitute Simon Lappin’s 80th-minute winner left the Tannadice side shell-shocked.
The defeat leaves the Tangerines second bottom in the table and was greeted with howls of derision from the angered trailing support.
The opening quarter suggested goals would not be hard to come by.
Michael O’Halloran utilised his blistering pace for the first time in the eighth minute to reach the byline on the right but a key deflection took his low cross just out of the reach of Cummins, who was poised to score on the edge of the six-yard box.
Two minutes later, O’Halloran’s header could not find a way through a crowded goalmouth as Saints started with their tails up.
However, they required a block from Tam Scobbie to prevent Adam Taggart’s shot from squeezing in at the back post in the 15th minute and two minutes later Mannus stooped to hold a first-time shot from the United striker at the end of a slick move from the visitors.
Just as the flow of play evened out again, controversy struck to reduce Saints to 10 men.
Scobbie’s header back was woefully short and as McKay reached the ball first, there was only going to be one outcome when Mannus arrived marginally later.
The penalty was no surprise but the red card that followed was debatable, as McKay had knocked the ball diagonally away from goal and other defenders were retreating to cover.
O’Halloran was sacrificed in favour of substitute keeper Zander Clark but the youngster’s first involvement was to retrieve McKay’s penalty from his own net.
Playing with a man less was a tall order for Saints but they rose to the occasion and were next to threaten five minutes from the interval when Cummins headed over a Liam Craig free-kick.
The home side will have known their best chance was to keep the tempo high and not allow United’s 11 men to dictate the pace and exploit the inevitable gaps against their 10, and they did just that after the interval.
Four minutes into the second half, Cummins caught Shaughnessy’s assist on the volley but his 12-yard effort was too straight to trouble United keeper Luis Zwick, who held easily.
The goalie was then not required a minute later but should have been, as Murray Davidson’s shot was deflected into the path of Steven MacLean, only for the striker to scoop his free shot over.
With Saints continuing to dominate, despite their one-man disadvantage, Craig’s curling free-kick was beaten away by Zwick in the 56th minute.
However, their pressure finally paid off in the 64th minute when Craig floated in a corner from the left and Cummins rose highest to nod into the top corner from six yards out.
The goal gave Saints even more belief and John Rankin did well to deflect a low Cummins shot round his own post in the 70th minute.
The McDiarmid Park hosts’ problem was always going to be maintaining their momentum with a man less but, just as United momentarily appeared to be getting on top, the Perth side stunned them by snatching victory.
It was a simple goal that won it. A long ball forward from keeper Clark was flicked on by Cummins and Lappin’s deft lob nestled in the net behind Zwick to earn all three points.