The Wednesday boss had promised two pals he would wear the traditional Highland dress once the Hillsborough side had avoided the drop.
Steve Coppell's, side who guaranteed promotion three weeks ago are after Sunderland's record points haul of 105 in 1999 and are two short, but with a final game at home to QPR next week the odds are in their favour.
Reading, chasing a 100 goals tally for the season, bombarded Wednesday in the opening minutes but could find no way past the resolute Sheffield defence as Drissa Diallo headed clear and full-back Frankie Simek hacked away a John Oster cross.
Wednesday, overrun in midfield, caught out Steve Coppell's side in the 26th minute. Injury-jinxed striker MacLean, making only his fourth start of the season, should have snatched the lead after Leon Best picked out Jon-Paul McGovern.
The Wednesday winger pumped the ball to MacLean but his close-range header lacked power and Marcus Hahnemann collected.
Reading broke the deadlock in the 34th minute with a sweet three man move, Kevin Doyle squaring the ball to Oster as goal machine Dave Kitson finished off from eight yards for his 21st of the season.
McGovern had a stinging drive stopped by Hahnemann before the Sheffield side pulled lever in the 57th minute after Simek was upended by Bobby Convey ,MacLean coolly sending the keeper the wrong way as he tucked the ball into the right-hand corner.
Substitute Steve Hunt headed a Doyle corner wide from six yards before MacLean almost grabbed a second with a shot on the turn that flashed inches wide of the far post with the keeper stranded.