The Owls slipped to a fourth successive defeat as Wycombe posted a maiden Championship win at Adams Park.
David Wheeler’s header on the stroke of half time was the difference of a close contest in Buckinghamshire.
Either side might have taken the points on the balance of play but Wheeler’s effort was the edge and Wednesday’s dry spell continues.
After a bout of early pressure from Wycombe, the Owls countered to go close 10 minutes in when Callum Paterson unleashed a fierce half volley that whistled wide.
Adam Reach flashed a dangerous cross into the danger zone moments later that just evaded Jack Marriott at the back post.
The hosts responded with Adebayo Akinfenwa planting a header past the post before play returned to the other end, where some brave defending from Anthony Stewart denied Paterson a clear header.
Paterson brought a flying save from Ryan Allsop before counterpart Joe Wildsmith made a super stop to thwart Horgan with half time looming.
But right on the whistle, Wycombe hit the front. Joe Jacobson swung a curling corner into the mix and Wheeler climbed high to glance into the top corner.
The goal and the timing of it was a hammer blow for Wednesday, who were in need of a spark after the break.
But the Chairboys looked the more likely in the early throes and only a smart Wildsmith save at full stretch denied Scott Kashket from distance.
The Owls rallied and Jacobson blocked a whistling Josh Windass shot on the angle.
Possession belonged to Wednesday as the second half unfolded but that cutting edge in the final third belied the approach play.
Substitute Izzy Brown injected some added quality in the middle of the park and the Owls piled on the pressure.
Wycombe had everyone behind the ball to protect their slender advantage and were on the back foot throughout the closing stages.
But the hosts threw bodies in the way of everything Wednesday had to offer and coupled with last-ditch defending held out to record their first win of the season
Wednesday: Wildsmith, Harris (Brown 60), Palmer, Iorfa, Börner, Reach, Bannan, Windass, Pelupessy (Kachunga 67), Paterson, Marriott (Rhodes 77)