Millwall recovered from trailing to complete a 2-1 win over struggling Premier League side Aston Villa in the fourth round of the FA Cup at The Den.
Having been emptied out of the League Cup semi-finals 4-3 on aggregate by League Two Bradford City on Tuesday, Paul Lambert's side looked set to get back on track when the recalled Darren Bent struck the opening goal on 22 minutes.
But their defensive struggles in dealing with cross balls were exposed again as Danny Shittu headed the equaliser on 27 minutes before John Marquis popped up with one minute left of normal time to condemn Villa to another demoralising defeat.
Lambert's relegation-haunted side have won only four league games all season and are fourth from bottom of the Premier League before they host Newcastle United at Villa Park on Tuesday.
Sadly, the fantastic result for Kenny Jackett's side was slightly marred when a section of home fans began throwing missiles on to the pitch early in the second half.
Villa started like a team under pressure and looked nervy in possession, with Millwall only able to fire in a couple of harmless long-range efforts.
Lambert's side seemed to shake off their early worries and went ahead in the 22nd minute through Bent.
Fabian Delph robbed Liam Feeney of possession and Andreas Weimann capitalised, running on to the ball before forcing David Forde into action for the first time.
The Lions' goalkeeper could only palm Weimann's effort into the path of Bent, whose miskicked effort crept over the line to give the beleaguered top-flight side the lead.
The goal did not act as a calming influence on the Villa players, though, as they nearly conceded a quick equaliser when Shittu headed on to the roof of the net from a corner.
The lesson was not learnt, however, and just five minutes after falling behind the hosts were level, as James Henry's corner found Shittu at the back post and the Millwall skipper rose to power a header past Shay Given.
The equaliser led to the nerves creeping back into Villa's game and meant the npower Championship promotion hopefuls went in level at the break.
A couple of set-pieces early in the second half again tested the visitors' resolve, and 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.
Once play had resumed it was Millwall who were once again on the front-foot, with Villa seemingly sapped of all confidence.
Shittu epitomised Millwall's drive as he marshalled his backline with his no-frills style of defending.
Villa substitute Barry Bannan arrowed in a shot that Forde again decided to push away but this time the ball bounced to safety.
The tie looked set for a replay at Villa Park until Millwall striker Marquis headed Adam Smith's cross on to the bar before reacting quickest to nod home the rebound.
The earlier incident from the Millwall fans meant their side had to negotiate six minutes of stoppage time before becoming the first name in the hat for round five, but they did so with relative ease to leave Lambert suffering one of his worst weeks in management.