Wednesday went down to a 1-0 defeat at Peterborough as a Grant McCann free kick was the difference in a hard-fought basement battle.
In an ultimately fruitless afternoon, the Owls created little to trouble Posh, who gave their safety hopes a significant shot in the arm.
But Dave Jones’ side head into next Saturday’s season finale against Middlesbrough at Hillsborough with their destiny in their own hands, knowing victory will guarantee survival.
On another day of Championship drama that saw Wolves slip closer to the trapdoor, the Owls went into the London Road clash knowing a point would secure safety.
And backed by 5,000 travelling fans, they started brightly enough, as did the home side through the early exchanges.
Ten minutes in, the first opening came and it went Peterborough’s way. Lee Tomlin carved a chance from relatively little and forced a fine save from Chris Kirkland.
The ball rebounded back to Tomlin, who squared to Dwight Gayle, but Miguel Llera was on hand to clear the danger as the Posh marksman was about to pull the trigger from close range.
Danny Pugh then thwarted Gayle at the back post following a deep cross from McCann before the Owls almost profited from their first chance of the game on 26 minutes when a Giles Coke snapshot was well saved by Bobby Olejnik.
The Posh keeper then came to the rescue from the resulting corner when Pugh’s flag kick was directly on its way into the back of the net.
Seyi Olofinjana blasted goalwards moments later as Wednesday enjoyed a brief purple patch and it took a brave block from Gabriel Zakuani to deny the loanee midfielder a maiden goal for his temporary employers.
Play evened out as the interval approached but both sides had sights of goal, with a Gayle shot smothered by Kirkland before Anthony Gardner headed narrowly wide from another dangerous Pugh corner.
The Owls enjoyed the better of possession after the restart, limiting Posh to scant opportunities from distance, without asking too much of Olejnik at the other end.
But everything changed on 64 minutes, when Peterborough stole into the lead.
Wednesday conceded a free kick 25 yards from goal and McCann struck an unstoppable angled drive that flew past Kirkland.
With the celebrations barely over, Posh almost immediately doubled their advantage.
Nathaniel Mendez-Laing burst down the right and sent in a teasing low cross that just evaded the onrushing Gayle as the hosts turned the screw.
Kirkland then saved from Tomlin at the near post and Wednesday were desperate for an outlet to avert the pressure.
They did improve to that end in the closing stages and substitute Leroy Lita had a double chance to snatch a late point but his first shot was saved by Olejnik and the second blasted wide.
Peterborough: Olejnik, Alcock, Zakuani, Bostwick, Tomlin, McCann (Ferdinand 84), Rowe, Payne, Pritchard (Barnett 83), Gayle, Mendez-Laing (Newell 81)
Unused substitutes: Day, Brisley, Knight-Percival, McDonald
Owls: Kirkland, Buxton, Llera, Gardner, Pugh, McCabe (Lee 46), Olofinjana, Coke, Helan (Lita 66), Maguire, Howard (Madine 73)
Unused substitutes: Bywater, Taylor, Mattock, Semedo