Millwall piled on the misery for beleaguered Aston Villa manager Paul Lambert as John Marquis's late goal gave the Championship club a 2-1 win in the FA Cup fourth round on Friday.
Lambert has endured a torrid time since leaving Norwich to take charge at Villa Park in the close-season, but this week has been a new low for the Scot, whose Premier League team were knocked out of the League Cup semi-finals by fourth tier minnows Bradford on Tuesday.
Villa desperately needed a victory at the Den to get back on track after that humiliation and looked on course when Darren Bent opened the scoring midway through the first half.
But Nigerian defender Danny Shittu headed Millwall level soon after Bent's goal and young striker Marquis punished Villa's defensive frailties with the last minute winner.
Lambert insisted earlier this week that Villa owner Randy Lerner has assured him he won't be sacked, but this latest embarrassment will only increase the pressure on the former Borussia Dortmund star.
While Millwall, FA Cup runners-up in 2004, can celebrate a place in the last 16, their victory was slightly marred when a section of home fans began throwing missiles on to the pitch early in the second half.
After a nervous start, Lambert's side seemed to shake off their timid approach and went ahead in the 22nd minute.
Fabian Delph robbed Liam Feeney of possession and Andreas Weimann capitalised, surging away from Shittu before forcing Millwall goalkeeper David Forde into action for the first time.
Forde could only palm Weimann's effort into the path of England striker Bent, whose miskicked effort crept over the line.
But with Villa's star striker Christian Benteke rested there was a lack of bite about the visitors and Millwall quickly regained a foothold in the game.
Villa have been weak at set-pieces for much of the season and Millwall looked to exploit that through Shittu, who headed onto the roof of the net from James Henry's corner.
Lambert's men failed to heed the warning and the hosts equalised in the 27th minute when Lions captain Shittu met another Henry corner at the far post and powered a header past Shay Given.
Feeney came close to putting Millwall ahead when he fired just wide following a corner before the hosts' momentum was brought to a halt by their own supporters.
The game was stopped for five minutes just before the hour-mark due to a disturbance amongst Millwall fans in one corner of the Dockers Stand, with several bottles thrown in the direction of the assistant referee Mark Scholes after he awarded a free-kick to Villa.
Villa substitute Barry Bannan fired in a shot that Forde pushed away as the visitors launched a rare second-half attack.
But, with a replay at Villa Park within reach, Villa were shattered in the 89th minute when Marquis, making his first start of the season, headed Adam Smith's cross on to the bar before reacting quickest to nod home the rebound.