Kayden Jackson struck early for Ipswich and a Dominic Iorfa own goal after the break looked to have given league leaders Ipswich victory at Hillsborough.
But a determined Wednesday showed immense powers of recovery to earn a dramatic point with strikes from George Byers and Michael Smith.
And it was no more than the Owls deserved from a ding-dong encounter that could have gone either way, although a draw was probably the right result.
An explosive start saw one incredible near miss and a goal that promptly followed.
With just two minutes on the clock, Barry Bannan took possession inside the centre circle and looked up to see Christian Walton out of position and off his line.
The Owls skipper executed an outrageous dipping volley that seemed destined for the net but the ball bounced agonisingly over the crossbar from six yards.
And Ipswich maximised their good fortune by bursting into the lead two minutes later.
Jackson raced into the box from deep and showed power and poise to slot beyond the outrushing David Stockdale.
Thereafter, the first half unfolded as a relatively even affair, with both sides probing without calling either keeper into action.
The closest Wednesday came was Fisayo Dele-Bashiru standing up a delicious cross to the back post and Smith needed barely another inch in order to level.
Conor Chaplin sent a fierce drive wide at the other end and Liam Palmer responded by flashing an inviting feed across goal before the first half concluded with Ipswich holding their slender advantage.
The Tractor Boys strengthened their grip in the early throes of the second period, bossing possession, as Wednesday struggled to make an impact in the final third.
Then, another remarkable passage of play spawned two quickfire goals, one for each side.
On 71 minutes, Sam Morsy crossed from the right flank but in an attempt to clear from close range, Iorfa inadvertently sliced into his own net.
The Owls, though, hit back in the best possible way, halving the deficit two minutes later. Marvin Johnson took a short pass from Bannan and his superb angled cross fell perfectly for Byers to smash home in front of the Kop.
That set up a grandstand finish in an electric atmosphere and Wednesday duly delivered with a minute to go.
Reece James broke down the left of the penalty area, picked out Smith rushing into the box and the big striker planted a firm header past Walton to salvage the draw.
Wednesday: Stockdale, Palmer, Iorfa (Mighten 72), Ihiekwe, James, Johnson, Byers, Bannan, Dele-Bashiru (Gregory 57), Windass, Smith