Atdhe Nuhiu added to the list of late goals the Owls have poached at Rotherham when his last-gasp strike sent Wednesday through to the third round of the Carabao Cup.
A relatively even contest seemed destined for penalties until Nuhiu intervened with 96 minutes on the clock, sweeping home to give the Owls the edge once more over the Millers.
Nuhiu put his name alongside Kieran Lee and Dominic Iorfa from recent seasons to break Rotherham hearts with the curtain coming down at the New York Stadium.
There was little to separate the South Yorkshire rivals until the late drama, with both goalkeepers and the defenders in front standing firm.
When openings did arrive, they were stopped or missed, before Nuhiu had the final say with a clinical hit.
Lee Bullen shuffled his pack, making nine changes from Saturday’s trip to Preston, while the Millers were unchanged following their last league encounter at Burton two weeks ago.
And the full strength hosts were first to show when Freddie Ladapo drilled a well-worked corner narrowly wide and that prompted a mini period of home pressure.
Cameron Dawson was untroubled, though, and that might have spelled danger for Paul Warne’s side when Nuhiu was on the end of an Iorfa cross but Daniel Iversen smothered the big man’s header.
Rotherham replied with Ben Wiles slicing past the post from distance before there were chances at both ends inside a minute.
First, Jordan Rhodes headed into the grateful arms of Iversen from a whipped-in Morgan Fox delivery, then Ladapo prodded Michael Smith’s knockdown wide from 10 yards.
With half time looming Jacob Murphy had a fierce shot charged down by ex-Owl Richard Wood and Dawson was forced into a flying save by Smith to keep the score goalless.
The cup contest needed a spark after the break and the dangerous Smith almost provided it but was a whisker away from Matt Crooks’ driven feed.
Fox then thwarted Wiles at the last with a terrific sliding tackle as the midfield man was about to pull the trigger from close range.
Undaunted, the Owls motored upfield and Iversen denied Nuhiu on the angle after the striker evaded his marker and unleashed on goal.
The action was hotting up, with Dawson denying Wiles at his near post, while the impact of substitutes Kadeem Harris and Barry Bannan was more and more telling.
And Harris was the architect as Wednesday so nearly broke the deadlock nine minutes from time. The wideman sent a delicious cross right into the mix and Fox was inches off target with a powerful header.
But deep into stoppage time, the breakthrough finally came and it was no surprise to see Harris at the heart, sending an inviting ball to the back stick where Nuhiu stabbed high into the net.
Wednesday: Dawson, Iorfa, Bates, Thorniley, Fox, Murphy (Bannan 65), Pelupessy (Forestieri 76), Luongo, Winnall (Harris 46), Nuhiu, Rhodes