Goals either half from Atdhe Nuhiu and Michail Antonio gave Sheffield Wednesday a two-nil lead, but two-goals in 15-minutes by Doncaster meant the match finished level at 2–2.
Into the dying seconds of five-minutes added time and Millwall managed to find space for a shot and scored with virtually the last kick of the game, with the match ending 1–1.
In the 37th minute, former Sheffield Wednesday player Michail Antonio wriggled into space and lifted the ball into the box, where Henri Lansbury had ghosted in unattended to nudge a free header past Keiren Westwood to give the away team the lead into the first-half.
However, it was harshly disallowed due to the referee claiming that Atdhe Nuhiu had fouled the defender in the build-up to Stevie May's shot and denying his second goal of the season.
Reading had a series of more chances in the second, but Sheffield Wednesday made them pay for their missed opportunities, as Stevie May put in a deflected free-kick to give the mighty owls their first victory at Hillsborough since March.
But in the second-half, Manchester City scored straight away with Frank Lampard tucked in James Milner's cross soon after the restart before Edin Džeko swept in a pass from Jesús Navas, who added a ferocious drive.
Sheffield Wednesday tied it early in the second-half, Chris Maguire fizzed in a low cross from the right, prompting Morrison to slide in and inadvertently prod the ball beyond Marshall for an own-goal.
The home team were first to carve a clear cut chance as Tommaso Bianchi fed for Mowatt but Keiren Westwood was sharp off as line to narrow the angle and make the stop.
Souleymane Doukara then placed his slide rule finish just wide of the target and Rodolph Austin brought another smart save from Westwood as Leeds looked the more likely to score.
Jonathan Douglas had his attempt to put the home side in the lead headed clear from the line by Liam Palmer before Jota drilled over the bar, the match ended in a 0–0 draw.
Gary Taylor-Fletcher had a half chance on 67 minutes after a fine pass from Claude Dielna before Liam Palmer smashed into the side-netting having taken a clever back heel from Stevie May into his stride.
Gary O'Neil's free kick found Cameron Jerome in space and his header seemed goalbound only for Keiren Westwood to delve into the top drawer and prevent the opening goal.
The Republic of Ireland international promptly repeated the feat moments later to deny substitute Nathan Redmond, whose blistering low drive was diverted past the post.
The forward had fired a left-footed short narrowly wide of the post before opening the scoring with a quality run and shot, Wednesday's first goal in four matches.
The hosts nearly broke their home duck in bizarre circumstances when Atdhe Nuhiu pressurised Kirk Broadfoot into over-hitting his backpass to Adam Collin who saw his sliced clearance go just wide.
[58] Couple days before the game against Huddersfield Town, Sheffield Wednesday brought in their fourth loan signing this season, this time bringing in Lewis McGugan from Watford[59] and made his first start in that match.
Another penalty was denied in the late stages of the match when Chris Maguire was tackled by Joel Lynch, but the referee declared that The Owls forward was diving and booked him for it and the game ended in another 0–0 draw.
Then immediately from kick-off, Sheffield Wednesday equalized when Atdhe Nuhiu and he teed up unmarked strike partner May for a simple close-range finish past Latics goalkeeper Scott Carson.
The third came midway through the second half as Christensen converted from Hugo Rodallega's pass, before Woodrow added a fourth from the spot after Patrick Roberts had been fouled by Claude Dielna.
The Owls went close to doubling their advantage when Maguire's low cross from the left deflected onto the crossbar, before Miller was booked for turning Tony McMahon's centre into the Wednesday goal with a hand.
Lewis McGugan was a constant threat for Stuart Gray's side and struck from range to test Scott Carson, while at the other end, McClean pounced on Ben Watson's delivery to score after the break, only for the linesman's flag to cut short his celebration.
Wednesday, the lowest scorers in the division before kick-off, shaded proceedings and though a stalemate looked likely, they took advantage of Callum McManaman's recklessness after doing a two-footed challenge on Claude Dielna.
Nuhiu saw a header saved by Carson quickly after the dismissal but beat the Wigan keeper a minute later when he powered home Jérémy Hélan's cross to secure Wednesday's fourth win in six matches.
It was a brilliant first-half performance from the away side, scoring the opening goal after 14 minutes when Atdhe Nuhiu fired home at the end of a flowing move down the right that also involved Stevie May and Kieran Lee.
But in the second-half, the hosts equalised almost immediately after sending on their two playmakers Silva and Nasri, with the pair linking up on the left of the Owls' box and playing in Milner to convert his second goal of the season.
Manuel Pellegrini's men took control from that point and Milner shot wide, while Silva had an effort well saved as the Premier League side desperately looked to avoid a replay.
Looking to reply immediately, Sheffield Wednesday was awarded a penalty three minutes later and Chris Maguire placed it perfectly in the right side of the net to make it 2–1.
Then Clayton Donaldson, who had scored five times in his previous three games, narrowly failed to connect with a centre from left-back Jonathan Grounds just before the break before keeper Keiren Westwood was forced to turn over a powerful drive from winger David Cotterill.
Things did not improve after the break as home striker Atdhe Nuhiu was off target with a couple of efforts and Cotterill shot wide for Birmingham and the match finished a stalemate.
Both sides started at a frenetic pace and Simon Cox had the first chance of the game for Reading as he tried to bend the ball round Keiren Westwood's right hand, but the keeper made a decent save.