Chelsea sensationally avenged their bitter Premier League defeat to Manchester United as they won an nine-goal Capital One Cup thriller 5-4 after extra-time at Stamford Bridge.
United looked set to pile on the misery for the European champions with a 3-2 fourth-round victory three days after ending their 10-year wait for a league win in west London, in the most controversial manner imaginable.
But Eden Hazard scored a penalty with the last kick of normal time before Daniel Sturridge and Ramires completed an amazing comeback just 24 hours after Arsenal's astonishing 7-5 win at Reading.
Just as in that game, defending was nowhere to be seen as United led three times through Ryan Giggs, Javier Hernandez and Nani and Chelsea hit back with a David Luiz penalty and Gary Cahill header.
Giggs also scored an extra-time consolation from the spot for United as the Mark Clattenburg saga was briefly forgotten.
The 6,000 United fans, far more than on Sunday, mercilessly taunted their opponents throughout about both Clattenburg and the John Terry scandal, briefly unfurling a banner which read "Clattenburg: Referee, Leader, Legend'' and engaging in several chants, including "Justice for Clattenburg".
Chelsea boss Roberto Di Matteo resisted the temptation to rest the two players at the centre of the current storm, John Obi Mikel and Juan Mata among only six survivors in both starting line-ups from Sunday's acrimonious clash.
It all started tamely enough, Sturridge doing his best Fernando Torres impression by falling over the ball when clean through.
And Chelsea invited ridicule again when they fell behind for the fourth straight game midway through the half.
Alexander Buttner's free-kick flew wide and Petr Cech inexplicably chose to play a short goalkick to Oriol Romeu, who was facing his own goal and completely unaware Anderson was perfectly placed to rob him and feed Giggs to sidefoot home.
Lee Mason had already upset the home fans by booking Romeu and when Mikel was deservedly shown yellow, it prompted chants of "You're worse than Clattenburg'' from the home supporters.
But they were cheering the referee's decision on the half-hour mark when Buttner clumsily brought down Moses in the box.
Luiz crashed home the penalty in front of the United fans, sparking just the kind of scenes the fixture did not need.
A firework or flare was thrown into the penalty area, while a supporter in the away end invaded the pitch and returned to the stand before he could be caught.
The United fans let off another flare as they retook the lead two minutes before the break.
Luiz's surge upfield backfired spectacularly, Anderson feeding Hernandez, who held off two men before curling beyond Cech.
Both sides made half-time changes, Ramires replacing Mikel and Buttner withdrawn for Nick Powell, whose skidding drive forced a desperate save from Cech almost immediately.
An equally vital intervention from Rafael prevented Sturridge scoring a sublime solo goal, but the striker had no excuse from the resultant quick corner which he inexplicably tried to backheel in while Lindegaard was napping.
It did not matter as Chelsea equalised again in the 53rd minute thanks to another excellent piece of officiating, this time by one of Mason's assistants.
Cahill powered a header goalward from Mata's corner and although Rafael nodded clear, he did so from behind the goalline.
Chelsea sent on Hazard for Lucas Piazon in search of victory but fell behind again just before the hour mark.
United ruthlessly exploited the time and space they were given on the edge of the box before Nani played a one-two with Anderson and brilliantly clipped the ball over Cech.
Hernandez wasted a glorious chance from a rebound and Moses and Cesar Azpilicueta did likewise with headers.
Oscar soon joined the fray and instantly fed Mata, whose shot was handled in the box by Michael Keane but no penalty was given.
Moses shot too close to Lindegaard before Azpilicueta's desperate lunge kept Chelsea in it.
There was no joy for Mata from a free-kick in a similar position to that he scored from on Sunday, and Sturridge screwed another shot straight at Lindegaard.
Oscar's blockbuster was too close to the goalkeeper in the dying moments, which United looked certain to see out but for another suicidal mistake from Scott Wootton, who bundled Ramires over in the box in the fourth minute of stoppage-time.
This time, Hazard took the penalty, sending the ball straight down the middle with the final kick of the 90 minutes.
United tried to regroup in extra-time but Wootton's confidence was shot and he produced an even more horrific mistake in the seventh minute, nodding a long ball straight to Sturridge, who rounded Lindegaard to score.
Cahill glanced a header just wide and Keane was lucky to see only a yellow card for a cynical last-man foul on Sturridge, Luiz crashing the resultant free-kick against the crossbar.
Moses should have killed the game when put clear by Sturridge but Ramires finally did after unselfish work by Hazard.
That was fortunate as Azpilicueta knocked over Hernandez in the final minute and Giggs made it 5-4 from the spot, but Chelsea held on.