If the Baggies avoid defeat against Crystal Palace tonight, O'Connor and Sheffield Wednesday will live to fight another day.
If Palace win, however, Wednesday are condemned to life in League One next season; no get out of jail free cards, no way out.
Irish midfielder O'Connor has been one of the shining lights for the Owls this season; if only the rest of his team-mates had displayed the same grit and determination, relegation would not have been an issue.
But now, after extending a winless run to six games in this five- goal thriller at Cardiff City, the Owls need a favour.
Unfortunately for O'Connor, just about everyone he knew at The Hawthorns five years ago has now moved on.
"I don't have any contacts left down there now," he admitted. "All my friends have gone. I just hope they go and give a good account of themselves.
"It's far from ideal that we have left our destiny in someone else's hands. It is rubbish really," he added.
"We needed to look after ourselves in this situation. We needed to come here and beat Cardiff and keep our fate in our own hands.
"We had good chances and we haven't taken them and we gave away poor goals. To be honest, that is a recipe for disaster."
Having already secured play-off qualification, Saturday's opponents Cardiff rested three players but were still far too good for the Owls.
For Wednesday's sake, it's to be hoped the same applies to already-promoted West Brom.
Owls manager Alan Irvine made one change to his side – dropping striker Leon Clarke to the bench and recalling midfielder Tom Soares – with winger Jermaine Johnson pushed into attack.
The Owls made a shaky start and were indebted to goalkeeper Lee Grant for saves that denied both Joe Ledley and Jay Bothroyd
But the Owls were unlucky not to go ahead after 13 minutes when Darren Potter's free-kick was pushed onto the post by Cardiff goalkeeper David Marshall. Just moments later, Johnson broke the deadlock, finishing off a three-man move with a simple tap-in at the far post.
After the controversy sparked by his challenge on Richard Cresswell in the Steel City derby, the goal could have guaranteed the Jamaican better headlines.
However, the Owls managed to hold onto the lead for less than two minutes and it was a freekick given away by former Cardiff defender Darren Purse that proved costly.
Purse tripped Peter Whittingham on the edge of the box and, after dusting himself down, the Cardiff winger curled a shot over the wall and beyond Grant.
Apart from the inability to hold onto the lead, the Owls had every reason to feel satisfied with their first-half display. The home side had done more defending and the visitors had dictated the tempo.
Irvine's men had also showed more invention in the final third than of late but they still lacked a cutting edge.
As half-time approached, Grant clawed a header from Michael Chopra to safety after rushing off his line to meet the Cardiff striker.
Wednesday's failure to take their chances has been a frequent cause of concern for manager Irvine and his side were again guilty of profligacy just before the break.
Tom Soares failed to get any real power on a header when unmarked just a few yards out and Marcus Tudgay took one touch too many after a good ball across the box from Eddie Nolan.
Those misses would prove pivotal as the Owls lost Johnson to a recurrence of a hamstring injury at half-time and then rapidly began to crumble.
Mark Beevers was lucky to get away with a horrendous ball out of defence that nearly set up Kelvin Etuhu.
But the Owls were carved open again, moments later, as Bothroyd ran onto a ball over the top from Stephen McPhail and scored with the minimum of fuss.
Purse should have stayed with his man and Grant should have been better positioned.
With Watford cruising to a victory at home to Reading, things could hardly have gone worse for the Owls.
Irvine sent on Francis Jeffers and Etienne Esajas in a bid to turn things around and was initially rewarded.
Dutchman Esajas, who had gone close with his first touch, sent a perfect cross over to Tudgay and the Owls striker slid the ball through Marshall's legs from a tight angle.
It was a shock lifeline for the Owls but once again they pressed the self destruct button and allowed it to slip.
This time, substitute Leon Clarke was at fault, making an error with sloppy play in midfield.
Having surrendered possession, the Owls then allowed Bothroyd to run 15 yards, skipping a challenge from Purse, before shooting past Grant.
Wednesday's misery was complete in stoppage time when a shot from Esajas struck the inside of the post and rolled across the line to safety.
The reaction of the Wednesday players at the final whistle told its own story.
Survival now rests on a knife-edge and all eyes will be fixed on the televised Palace game tonight.
Cardiff City: Marshall; McNaughton, Gerrard, Blake (Hudson 45), Capaldi; Etuhu (Burke 59), McPhail (Wildig 66), Ledley, Whittingham; Bothroyd, Chopra. Unused substitutes: Enckelman, Quinn, Matthews, McCormack.
Sheffield Wednesday: Grant; Nolan, Beevers, Potter, Spurr; Varney (Esajas 69), O'Connor, Potter, Soares (Jeffers 63); Johnson (Clarke 45), Tudgay. Unused substitutes: Buxton, Hinds, O'Donnell, Gray.
Referee: P Taylor (Hertfordshire).
Hero: Etienne Esajas
The Dutch winger did more in 21 minutes than some of his team-mates managed in 90. Nearly scored with his first touch, set up Tudgay's equaliser, and hit the post in stoppage time.
Villain: Darren Purse
After a string of impressive performances, the Owls captain slipped back into his old ways against his former club. Might have prevented all three goals.
Key moment: 40th minute
With the score at 1-1, Owls midfielder Tom Soares wasted a gilt-edged chance to restore the lead with a poor header.
Ref watch: Paul Taylor
Paul Taylor: Accomplished display by the man in the middle. No controversies and no question marks over any of his decisions.
The Owls failure to defend properly after scoring goals was their Achilles heel and this defeat has pushed them to the brink of relegation.
Crystal Palace, home, Sunday May 2, Championship.
Quote of the day
They won't want my sympathy just like I didn't want theirs last season.
– Cardiff manager Dave Jones reflects on conflicting fortunes.
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