The 19-year-old England youth international, rated highly by United boss Sir Alex Ferguson and on loan until Christmas, tormented the Sheffield side's Yorkshire rivals in front of a 30,000 crowd.
Wednesday snatched the lead after full-back John Hills was fouled on the edge of the Leeds area. Eagles pumped in a teasing free-kick from 25 yards leaving keeper Neil Sullivan flat-footed as the ball curled into the far corner.
Paul Sturrock's side were inches away from a second six minutes later with the impressive Eagles again carving out the opportunity.
His cross from the right flank was met by Lee Peacock whose shot was blocked and Glenn Whelan saw his follow-up low drive deflected wide of the post.
Eagles set up Chris Brunt minutes later by pumping in another inch-perfect cross before picking out Peacock eight yards from goal but the striker's low drive was blocked by Sullivan.
Leeds, pegged back by the impressive Eagles, were foiled by David Lucas on 33 minutes when midfielder Eddie Lewis picked out centre-back Sean Gregan whose stinging header was saved at the foot of the post by the diving Wednesday keeper.
David Graham squandered a half chance minutes after the restart when running on to a Brunt pass but from 20 yards he pulled the ball well wide of the far post.
Full-back Frankie Simek tried a long range strike on 65 minutes but drilled the ball straight at Sullivan.
Sullivan brought off a stunning save in the 70th minute by finger-tipping Graham's fierce header over the top with Eagles again the architect.
Leeds overran Wednesday as they battled for an equaliser with substitute Robbie Blake and Rob Hulse both going close before Brunt rattled the United crossbar with a spectacular 30-yard strike.