UNITED 1 (Becchio 37), CHELSEA 5 (Mata 46, Ivanovic 65, Moses 66, Hazard 81, Torres 83)
United: Ashdown, Byram, Pearce, Lees, Peltier, Thomas (White 68), Green, Brown (Norris 72), Tonge, Diou (McCormack 73), Becchio. subs: Kenny, Varney, Gray, Somma,
Chelsea: Cech, Ivanovic, Luiz, Lampard, Torres, Mata (Ferreira 86), Oscar, Moses, Marin (Hazard 61), Azpilicueta, Bertrand (Cole 74) Subs: Turnbull, Piazon, Saville, Ake.
Referee: A Marriner
Elland Road was sold out for a Capital One Quarter-Final clash that pitted Leeds against old rivals Chelsea for the first time since May 2004.
Neil Warnock's side had won four out of the last five league games and he made a handful of changes, while Chelsea had only arrived back from Japan 48 hours earlier after their World Club Championship defeat.
United went on the attack first, El-Hadji Diouf getting in behind the Chelsea defence, but the visitors showed their quality with an incisive passing move that saw Jamie Ashdown beat away a shot from Victor Moses.
The fixture has a history of fiery matches and after Michael Brown was involved in one early altercation with David Luiz, Frank Lampard was booked for a challenge on Diouf.
United certainly started lively and some quick thinking from Petr Cech denied Jerome Thomas after some sloppy defending. But it was Ashdown who was called upon to make another good save when he got down well to another Moses strike.
United were certainly making Chelsea work hard and another decent attack saw Cech smother a far post header from Paul Green.
And Leeds were in front before half-time when Thomas escaped down the wing after an incisive break and Luciano Becchio was on hand to convert his low cross. Elland Road erupted when the South American stroked the ball past Cech, and it was very much game on.
The visitors' response came courtesy of Lampard, who forced Ashdown into making his third good save of the game.
But United had a great chance to double the advantage in the moments leading up to half-time, Tom Lees heading a Diouf cross over the bar.
There was still time for Ashdown to make another great save, getting a hand to a long distance effort from Lampard, but it was United who went in a goal to the good at the break.
But the visitors did take the lead within 60 seconds of the restart when a Juan Mata shot from distance crept inside of Ashdown's near post.
The game was still remarkably open, though. United continued to take things to Chelsea and put pressure on the visitors. In return, Chelsea were incisive in their movement, and Ashdown was called upon to make a good save to deny Fernando Torres.
The United goalkeeper also made another good save from Lampard, but he could do nothing when Branislav Ivanovic made a darting near post run to squeeze a header home from a good cross.
And it was 3-1 to the visitors a minute later when Moses did well to work himself an opening before firing home with a sweet strike from distance.
Chelsea added a fourth with 10 minutes remaining when, with Leeds pressing and leaving space, Eden Hazard was able to latch on to a through ball before picking his spot to tuck the ball beyond Ashdown.
And it was 5-1 within three minutes when Torres was able to convert after Ashdown had made an initial save.
That gave the scoreline a harsh look in Chelsea's favour, given that for over an hour the contest had been more than even.