West Ham United recorded their biggest victory over Manchester United in 80 years to dump the Carling Cup holders out of the competition.
Former Red Devil Jonathan Spector netted his first goals for the club to hand the Hammers a 2-0 half-time advantage before Carlton Cole put the icing on the cake with two second-half strikes of his own.
Victor Obinna was also in top form, providing assists for all four goals.
West Ham's superb all-round performance warmed the near-capacity crowd inside a snow-bound Boleyn Ground, with 33,551 supporters braving sub-zero temperatures to cheer their team on.
It was the away fans who had the most to cheer about early on as United made a strong start.
Indeed, only an outstanding save from Robert Green prevented Gabriel Obertan from giving Sir Alex Ferguson's side the lead on seven minutes. The England stopper dived to his right to push Obertan's shot onto the post, with the alert James Tomkins on hand to complete the clearance.
West Ham worked their way into proceedings and thought they had taken the lead nine minutes later.
Spector rampaged forward to the edge of the United penalty area before finding Obinna. His shot clipped the American on its way past Tomasz Kuszczak.
The goal appeared to had been given initially, only for referee Mark Clattenburg to consult with his assistant and correctly rule the effort out as Spector had strayed offside.
The decision led to a rise in the already cacophonous noise coming from the stands and appeared to inspire the Hammers.
On 22 minutes, the jeers turned to cheers as Obinna clipped a cross into the United penalty area for Spector to dive and sending a looping header beyond the grasp of Kuszczak.
The visitors came back strongly, with both Obertan and captain Ryan Giggs going close, but it was the hosts who would score the game's second goal.
Spector started and ended the move, bursting forward from midfield before passing to Obinna. The Nigerian scuffed his shot, but the American latched onto the loose ball before firing a left-foot shot past Kuszczak from close-range.
Obinna himself tried to get in on the act three minutes before half-time, only for the Pole to beat his low shot aside.
Into the second 45 minutes and it took just eleven of them for the Hammers to further extend their lead.
A quickly-taken free-kick from Tal Ben Haim found Obinna, who took a touch before finding Cole with an inch-perfect cross that the No9 headed powerfully into the net.
Ten minutes later, the outstanding Obinna teased substitute Rafael before sliding the ball inside for Cole, who held off his marker before slamming a left-foot shot past the advancing Kuszczak.
Hero Spector was delighted with his contribution against the club who brought him to English football as a 16-year-old.
"I don't think too many people were expecting that!" said the 24-year-old. "I was delighted with the result, most importantly, because we played really well. It was a great performance and a bit of a bonus getting the two goals."
"I think I have Victor to thank for both of them. He put a great ball in for the header and for the second one he went for the shot and nicked it a little bit and I was just there to pick up the pieces.
"I was a bit fortunate but it worked out great!
"The win at the weekend against Wigan was probably bigger for us, but hopefully we can continue on this track and push on from here.
"It's been a bit frustrating and disappointing but at the same time you have to wait for your chance and it came on Tuesday."