Francis Jeffers put his injury woes behind him to fire a crucial winning goal against Preston on New Year's Day at Hillborough.
Jeffers, who sat out over two months of the season with ankle ligament damage prior to this War of the Roses clash, came off the bench to convert a late penalty as the Owls won a crunch basement battle.
Karl Hawley had earlier put Preston into the lead but Akpo Sodje restored parity before Jeffers settled an entertaining S6 clash.
Brian Laws welcomed winger Jermaine Johnson back to the starting line-up after the Jamaican international sat out the previous two games on the road against Burnley and Hull respectively.
And it was Johnson at the centre of the game's first meaningful attack, displaying trademark trickery down the right flank to earn a free kick inside five minutes. Burton O'Brien floated over a hanging cross that was comfortably taken by Andy Lonergan in the Lilywhites' goal.
Preston responded a minute later by forcing a corner that failed to trouble the home defence. Sean St Ledger then headed Paul McKenna's set-piece wide of Lee Grant as the visitors tried to stamp some authority on the contest.
Wednesday earned a free kick of their own right on the edge of the penalty area when Richard Hinds was impeded but O'Brien's effort found only the Preston wall.
The game was rapidly developing into an open, end to end encounter, which belied the enormity of the result given both sides' precarious placing in the Championship table.
Simon Whaley was next to threaten for Preston, firing a rasping drive from distance that forced Grant into action; the keeper spectacularly tipping over his crossbar to deny the one-time Owls target.
Whaley was proving a thorn in the Wednesday side as the first half unfolded, twice sending teasing balls into the box from which Paul Gallagher and Lewis Neal almost profited. Darren Carter thumped a vicious long ranger over the bar as the visitors began to turn the screw.
Wednesday came close when St Ledger's underhit backpass allowed O'Brien a half-chance on 34 minutes but Lonergan cleared the danger right at the last.
A minute later, though, the Lancashire outfit swept into the lead. Lee Bullen misplaced a pass that landed at the feet of Hawley and the striker rounded Grant to net following his first start under new boss Alan Irvine.
The Owls made a double substitution at half time in a bid to up the ante in the final third. Jeffers replaced Deon Burton while Etienne Esajas came on for Johnson.
The move had the desired effect as Esajas in particular saw plenty of the ball during the early throes of the second period. Twice in as many minutes, the Dutchman showed good feet to pose a threat to the Preston defence from his right-wing berth.
The early pressure paid dividends as Wednesday drew level on 51 minutes. Lonergan misjudged a long punt upfield from O'Brien, leaving Sodje the simple task of advancing into the area to find an empty net from eight yards.
The Owls almost made it two moments later as Esajas hit a left-footed curler from which Lonergan made amends for his error with a flying save.
Esajas was causing all sorts of problems for Preston, not least in the 55th minute when he took a neat crossfield ball from O'Brien to beat two defenders before hitting a fierce drive that looped wide following a late intervention from Matthew Hill.
Jeffers got in on the act two minutes later, finding space to hit an angled daisycutter that Lonergan was relieved to see fly past his right hand post.
Wednesday were squarely in the box seat but were almost undone by a sucker punch on 66 minutes. Whaley found space down the right to deliver a curling cross that found Hawley at the back stick but his firm header was superbly pushed on to the woodwork by Grant. Hawley moved fast for the rebound but Grant was quicker still as he spooned away to safety.
The Owls' response was swift as Esajas cleverly played Glenn Whelan in but Lonergan moved sharply from his line to deflect the Irishman's effort wide for a corner. Sodje then forced a desperate diving save from Lonergan as Wednesday poured forward in pursuit of victory.
Esajas came within a whisker of achieving exactly that with 12 minutes left on the clock, unleashing a dipping shot from 25 yards that fizzed narrowly over the crossbar in front of the travelling fans from over the Pennines.
Preston made a double change on 79 minutes with Neil Mellor and Andy Carroll entering the fray and the latter almost bagged a winner in an instant. Mellor delivered a perfect low cross from the right but his fellow substitute dragged a simple chance wide with the Kop goal gaping.
And the visitors were made to pay for that profligacy when Hill handled substitute Marcus Tudgay's pass in the box in the 82nd minute. Referee Hill pointed to the spot and Jeffers stepped forward to seal three huge points for Wednesday.
SWFC: Grant, Bullen (c), Hinds, Beevers, Spurr, Johnson (Esajas 45), Whelan, Folly (Tudgay 71), O'Brien, Sodje, Burton (Jeffers 45)
Unused subs: Gilbert, Lunt
Preston: Lonergan, St. Ledger, McKenna (c), Davidson, Hill, Neal (Ormerod 88), Whaley, Carter, Chilvers, Hawley (Carroll 79), Gallagher (Mellor 79)
Unused subs: Neal, Sedgwick
Attendance: 20,690
Referee: Mr K. Hill
