Preston hit back with a late leveller to deny the Owls a second successive Hillsborough victory.
Richard Chaplow was the saviour for the Lilywhites, firing in a simple chance to cancel out Sean McAllister's maiden goal at Hillsborough.
The visitors were decent value for a point, showing strong character to bounce back after coming under the cosh during the first hour.
Wednesday might have increased their advantage but failed to strengthen their grip and were duly made to pay.
The Owls made two changes from the side that crashed 4-1 at Wolves last week, with new loan recruit Tony McMahon coming into the rearguard for broken leg victim Richard Hinds. Steve Watson dropped to the bench to accommodate Marcus Tudgay, who returned to the starting line-up having recovered from a thigh strain.
McAllister lobbed an early effort over the crossbar as the Owls started brightly in the Hillsborough sunshine. Jermaine Johnson, beginning the game on the left flank, was causing problems for full back Billy Jones and the Jamaican did likewise to Matthew Hill down the right after swapping sides with Etienne Esajas to keep the visitors on their toes.
Wednesday came within a whisker of taking the lead on 17 minutes with Johnson the architect, sending Tudgay racing through on the right side of the box. The striker's jabbed effort across Andy Lonergan beat the Preston keeper but fell the wrong side of the post.
The Owls kept up the pressure and took a deserved lead in the 21st minute. Lonergan failed to get good purchase on Tommy Spurr's long throw and the ball fell kindly on the edge of the penalty area to McAllister, who calmly sidefooted into the Kop net.
Preston fans had to wait until the half-hour mark to see their side muster an effort of note as Chaplow thumped in a daisycutter that Lee Grant saw safely past his upright.
Esajas and Spurr linked up well down the left but Lonergan was equal to the latter's cross on this occasion as the balance of play remained well in Wednesday's favour.
Johnson fired into the sidenetting just before half time after beating Hill for pace and the defender went into the book moments later for a blatant trip as Johnson again was too quick down the right flank.
The second half started as the first had ended with Wednesday in the driving seat and the hosts almost doubled their lead on 50 minutes. Esajas swung over an accurate corner from which Deon Burton steered a firm header goalwards only to see Chris Sedgwick chest the ball clear on the line.
Preston introduced Ross Wallace and Karl Hawley from the bench in a bid to improve what was a lacklustre performance in the final third. The double move certainly injected new life into the visitors and Sedgwick tested Grant just past the hour with a near post drive that the Owls keeper parried round the upright.
Sedgwick and Jones both had fierce shots charged down as Preston really started to threaten and Chaplow saw a curled effort from 12 yards fall agonizingly wide following good work by Neil Mellor.
James O'Connor stabbed a half chance straight at Lonergan at the other end before Chaplow restored parity for Preston on 77 minutes. Sedgwick found space down the right and teed up the onrushing midfielder, who hit high into the back of the net from close range.
Owls (4-4-2): Grant, McMahon, Wood, Beevers, Spurr; Johnson (Smith 71), O'Connor, McAllister, Esajas; Burton (Clarke 87), Tudgay
Unused substitutes: O'Donnell, Gilbert, Watson
Preston: Lonergan, Mawene, St Ledger, Chaplow, Hill, Nicholson (Wallace 56), McKenna, Whaley (Hawley 60), Sedgwick, Jones, Mellor
Unused substitutes: Neal, Hart, Carter
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