The Owls' Under-18s ran out 2-0 victors after a resilient performance against top of the table Charlton at Middlewood Road.
Goals from Mason Duffy and Warren Clarke either side of half time put Wednesday ahead, while an impressive defensive display helped seal the win.
Wednesday made the better start, quickly asserting their authority with some fluid passing, quickly frustrating Charlton and winning a number of free kicks.
The first real chance came on nine minutes, with Franck Betra heading wide from a corner, before Duffy dragged agonisingly wide midway through the first half.
Duffy's time would soon come, however, with the team’s top goalscorer adding to his tally on the brink of half time, latching on to an in-swinging corner to head home from six yards.
The start of the second half set the tone for the rest of the contest, with Charlton proving quick on the break and dangerous in possession.
But the Owls' physical advantage soon began to tell, with centre half Brad Beatson repeatedly steering the ball out of danger in a tight and organised back four.
And Wednesday's determination paid off when they doubled their advantage just past the hour.
Great work from Matt Penney out wide saw the defender put in a pinpoint cross for Clarke to control and finish.
Despite the driving rain, Charlton ended up dry in front of goal as the Owls did enough to maintain their clean sheet and run out winners for the third time in as many matches.