Murphy’s 20th-minute opener paved the way for the day’s biggest upset and despite a 75th-minute equaliser from Villa substitute Nicklas Helenius, the visitors went up the other end and won it five minutes later from Flynn’s brilliant left-foot strike.

Murphy said: “We didn’t really pay attention to Paul Lambert’s comments. It’s up to them how they want to play in the FA Cup – we just knew we wanted to go through. And from the start of the week it’s not been about taking a draw. it’s been about winning.

“It’s a big day for the club to beat a Premier League team away from home. These are the days that you play for and, as the manager said to us downstairs, it is one for us to remember.”

Villa fans voiced their displeasure towards Lambert after an abject performance from the home side, although the Villa boss strenuously defended his comments in his post-match press conference and insisted they had been taken out of context.

Lambert could certainly not be criticised for his team selection as he made only three changes to the side that claimed a New Year’s Day win at Sunderland, but such a comparatively strong line-up made the perfomance and result even more damning.

The visitors, rapidly improving under boss Nigel Clough but still languishing at 18th in the League One table and coming off a New Year’s Day loss to Walsall, soaked up what passed for Villa’s attacking intent and pushed forward with flair and confidence.

From the moment Murphy cut in from the left flank and rammed home a deflected opener, there was a growing feeling around Villa Park that this would be the place where the third round day headlines would be written.

Lambert did his best to emphasise his disappointment, saying: “It was important for ourselves and our supporters and everybody else at Aston Villa. You want to try to have a good cup run and I never took it lightly.

“That was my strongest team and one which in my view was strong enough to win. You couldn’t fault their endeavour and work but we probably made the wrong decisions at the wrong times.

“The lads will be hurting from the good feeling of Wednesday to being knocked out. We’re down again so you have to pick them up and get them going and that’s my job. It certainly hurts, that’s for sure.”

Christian Benteke, starting his second straight game as he seeks his first goal since September, missed two glorious chances to equalise on the stroke of half-time as Villa briefly threatened to get back in the game.

But the Blades dominated the early stages of the second half, with Flynn in particular threatening to increase his side’s lead before Helenius fired a scarcely deserved equaliser from the left side of the box in the 75th minute.

Just when it seemed there would only be one winner, the underdogs responded in style, Chris Porter and Flynn both coming close before Flynn cut across the edge of the box and unleashing a powerful rising drive past Steer.

Cue delirium among the visiting contingent and more tough days ahead for Lambert, who rued Benteke’s series of missed chances but denied that the striker was lacking in confidence after his injury lay-off.

“On Wednesday I thought his confidence looked really high,” said Lambert. “He had a couple of chances and last year he would have scored. But I wouldn’t say it was lack of confidence, because on Wednesday he was excellent.”