A defensive horror show cost St Mirren dearly against Motherwell with their top six dream this season all but over.
The Buddies knew a win was imperative to have a realistic chance of a top half finish and made the perfect start when Eamonn Brophy slammed home the opening goal.
But a series of errors at the back were to undercut the Saints, the first of which saw Sean Goss net at the near post before Connor Shields raced clean through to chip stand-in keeper Dean Lyness just two minutes later.
The Saints looked to have got themselves back in the game when Conor McCarthy netted at the back post from a Jordan Jones corner.
But the Steelmen regained their lead just before half-time when Dean Cornelius inexplicably found himself in acres of space in the box to fire past Lyness.
The Fir Park side made sure of all three points deep into the second half thanks to a Richard Tait own goal, that came about after Kevin van Veen had sailed past Conor McCarthy into the box.
The Paisley side are now hoping for a miracle in their last game before the split against Rangers, needing a win while also requiring a host of other results to go in their favour next weekend.
The Buddies are also now just six points clear of St Johnstone in eleventh spot, who picked up a valuable win against Livingston.
Lyness was promoted into the starting XI due to Jak Alnwick's suspension, with Scott Tanser and Greg Kiltie both missing out altogether through injury.
Jordan Jones made a welcome swift return from a shoulder knock, with Ethan Erhahon and McCarthy also back in from the start.
There was a nervous moment for stand-in keeper Lyness early on when Kevin van Veen closed him down outside the box, with the chance eventually cleared by Joe Shaughnessy.
After a stuttering start Saints slowly worked their way into the game, with Jay Henderson earning a corner.
Ronan whipped in the delivery, with Marcus Fraser nodding over the bar from close range.
The opener came on the very next attack, as Ronan's cross in from the left wing was cleared away by Stephen O'Donnell but deflected off Sondre Solholm Johanson straight to Brophy's feet. He kept his cool to slide the ball past Liam Kelly into the net.
St Mirren's lead didn't last long though, as Goss found space in the box from a Shields cross and buried a low strike past a slow-to-react Lyness at his near post.
In the blink of an eye the hosts were ahead. A van Veen flick wasn't dealt with by skipper Shaughnessy, who hadn't noticed Shields lurking behind him. The 24-year-old raced through on goal before producing a deft chip over the onrushing Lyness to turn the game on its head.
The Buddies rallied and Brophy did brilliantly to turn his marker and burst into the Motherwell box after a clever pass from Ronan. His low finish beat Kelly but thundered back off the inside of the post before being cleared to safety.
The breathless first half refused to slow down, as Ethan Erhahon's poor clearance set up O'Donnell inside the Saints box. Lyness stood up well to beat his powerful strike away and keep his side just one behind.
That save proved pivotal as five minutes before the break St Mirren hauled themselves level. A Jones corner to the back post was flapped at by Kelly, with the ball eventually falling to McCarthy after a poor Motherwell clearance. He fired into the roof of the net from a couple of yards out.
The Buddies almost took a lead into the half-time break, with Kelly saving Fraser's dipping shot before Jones overcooked a pass that would have sent Brophy one-on-one.
As it turned out it was the Steelmen who went into the break one ahead, as McCarthy failed to deal with Joe Efford on the left wing who picked out Cornelius in an explicable amount of space in the box. The young midfielder had all the time in the world to pick his spot, with Lyness again perhaps culpable after a less than convincing attempt at a save.
The Buddies returned from the break with a spring in their step, with Ronan picking out Jones on the edge of the box. He fired a low cross into the box, with Bevis Mugabi clearing just before Brophy could turn home.
Lyness produced an absolutely incredible save from a Callum Slattery piledriver shortly after, expertly tipping the goal-bound strike onto the underside of the bar.
Efford almost turned in the rebound but Marcus Fraser managed to scramble clear.
Saints forced a series of corners as they hunted for an equaliser, the best of which was a low Jones effort that was inches from being turned in by Fraser.
The Buddies continued to press for a leveller but the Steelmen defence was much tighter in the second half than it had been in the first.
Robinson threw caution to the wind and sent on striker Alex Greive in place of tiring midfielder Erhahon with 20 minutes left on the clock.
Henderson cut in from the right wing but could only trundle a low strike into Kelly's welcome arms.
And Motherwell wrapped up all three points just a minute later. Van Veen sailed past McCarthy in the box before his cross bounced off Tait and past Lyness to finally sink the Buddies.
