One week later than for the rest of the participants, the quarter-final stage arrives for these two sides. Club historian Rick Glanvill and club statistician Paul Dutton look at fixture that can't help but stir memories…
The squad that travelled to Japan touched down on Monday afternoon and joined the rest of the fit players for training on Tuesday morning. Chelsea's challenge has now ended in four trophies this season without success; four remain to be won, including the Capital One Cup.
This evening's match is the first of six in three different competitions between now and 5 January, when we visit Southampton in the FA Cup. Should the scores be level at Elland Road after 90 minutes, 30 minutes of extra time will be played. If there is still no winner the tie will be decided on penalties.
Chelsea have won the last two shootouts, both in 20111/12, in this competition against Fulham, and over Bayern Munich in the Champions League final. The winners enter the semi-final draw alongside Aston Villa, Bradford City and Swansea City which takes place after the match.
Leeds United have been drawn at home in the League Cup for the sixth successive time. Their last campaign ended in a 0-3 defeat at home by Manchester United. This season they have seen off League One Shrewsbury Town, League Two Oxford United, and Everton and Southampton from the Barclays Premier League.
Leeds and their manager Neil Warnock may sense that the Blues are over-ripe for the picking after the fruitless long-haul trip to Japan. But to revisit an era when this special brand of Yorkshire-London enmity evolved, Chelsea felt that way when Tommy Docherty's Diamonds were set to play a semi-final against Liverpool in 1965.
Supposedly weary after a draining trip to Rotterdam to face Cologne in a European Cup quarter-final play-off, Liverpool were widely expect to find fresher Chelsea's pace and dynamism too hot to handle.
Psychologically already at Wembley for the first time, the Blues underperformed and lost. It would be two more years before we made it to the twin towers - by beating Leeds United in the last four.
That was a bitter, bruising encounter that helped create one of the few great rivalries in English football that owes nothing to geography, religion or economic competition.
The mutual contempt grew from familiarity born of a quick concentration of matches that genuinely mattered between 1962 and 1970: top-of-the-table clashes in the First and Second Division, cup semi-finals and finals.
From the controversial 2-2 draw between first and second in January 1965, to the bruising FA Cup final replay at Old Trafford in 1970 - the last of six meetings that season.
Leeds have always directed the most bile across the Pennines to metropolitan Manchester than down the M1. Chelsea would rather put one over Spurs or the Arsenal than knock Yorkshire's pride off its perch. But this pair of rivals remains bound by history.
More usually, these days, it's played out long distance - a chant overheard on television, nothing to do with the opposition faced; or the even now barely concealed loathing when a former player recalls those days.
That is because this is our first encounter in eight years. Symbolically, Chelsea were Leeds' final opponents in the Premier League in 2004 when they were relegated.
The two clubs, who gained promotion together in successive years in the early 1960s, took vastly divergent courses 40 years later. Chelsea's financial worries disappeared and the club set a trajectory towards league titles, domestic cups and becoming champions of Europe.
Leeds were engulfed by debt and dropped to the lowest position in their history - bottom of the third tier - just seven years after beating AC Milan in the Champions League.
They are currently 12th in the Championship, pressing for a play-off place, and about to face a crucial Yorkshire derby against high-flying Middlesbrough on Saturday.
That must be one of the considerations for Neil Warnock, a manager who was interviewed for the Chelsea post in June 1991. 'As time went on,' Colin Hutchinson, then chief executive at Stamford Bridge, later revealed, 'we had reservations. I certainly cooled.'
Hutchinson's boss, Ken Bates, was finally successful in hiring Warnock after becoming owner of the Elland Road club, a tenure he is likely to end this week.
Warnock has won two, drawn one and lost two against the Blues in the dugouts of Notts County, Sheffield United and QPR. Leeds' technical director, Gwyn Williams, was for many years a highly successful manager of Chelsea's youth set-up among other roles at the club.
The draw for the Europa League Rounds of 32 and 16 will be made on Thursday 20 December from 1pm. Chelsea are one of the 16 seeded sides for the last 32 and will be drawn first in a tie, playing the second leg at home. The Blues cannot be matched with any club from the same association - Newcastle or Spurs in the case of the non-seeds - in the Round of 32.
There are no seeds, orders of drawing, or association restrictions in the Round of 16 draw.
Chelsea's possible opponents in the Round of 32 are: Anzhi Makhachkala (Russia), Atlético Madrid (Spain), Borussia Mönchengladbach (Germany), Stuttgart (Germany), Napoli (Italy), Basel (Switzerland), Internazionale (Italy), Sparta Prague (Czech Republic), Bayer Leverkusen (Germany), Levante (Spain), Zenit St Petersburg (Russia), BATE Borisov (Belarus), Dynamo Kiev (Ukraine), Ajax (Netherlands).
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WE HAVE HISTORY
There is almost too much history between our two clubs. The standout encounter is the 1970 FA Cup final replay at Old Trafford, which still holds the record for the highest TV audience for a club football match of 18.5m.
The drama is well covered elsewhere, but the images of cocky, glamorous Chelsea and dour, professional Leeds were carved into football's ancient oak that evening in Manchester. Chelsea won with a last gasp goal from David Webb, off his cheek, after Jack Charlton could only flick on Ian Hutchinson's long throw.
Webb was handed his winner's medal in the dressing room by Brian Clough; he had been denied access to the award ceremony because he had traded shirts and was wearing the white of Leeds.
In 1984 manager Eddie Gray declared Leeds arrived at Stamford Bridge to prevent Chelsea from returning to the top flight as the top side in Division Two. 'For the honour of Yorkshire football,' he said, 'we want to see Sheffield Wednesday promoted as champions.' That honour lay in tatters by 5pm.
At half time chairman Ken Bates came on the pitch to request over-excited fans not to invade the pitch again - it had happened even before kick-off - until the end of the match.
It was already 3-0 by then. Pat Nevin was ghosting through the Leeds side and each Chelsea goal was marked by youngsters running onto the field. Opening goalscorer was Mickey Thomas (pictured below), Kerry Dixon went on to net a hat-trick. Late substitute Paul Canoville made it 5-0.
Today Chelsea and Leeds meet in a cup competition, including replays, for the 12th occasion, including the 1970 FA Cup final and replay at Old Trafford.
Chelsea and Leeds have crossed swords twice before in the League Cup: in 1969/70 and most recently in 2001/02 when we won 2-0. Frank Lampard was playing his 17th game for the club.
That victory was our only one in our last five visits to Elland Road. Leeds have won two and there have been two draws. Our last visit was in December 2003 in the Premier League. Jermaine Pennant and Damien Duff secured a 1-1 draw. Both John Terry and Frank Lampard started for the Blues.
In all competitions, Chelsea have only won six times at Elland Road in 48 attempts.
Previous League Cup meetings
3rd round, 24 September 1969
3rd round replay, 6 October 1969
Other cup meetings (all FA Cup)
1936/37 - 3rd round Stamford Bridge - Chelsea won 4-0
1951/52 - 5th round Elland Road - Drew 1-1
Replay - Stamford Bridge - Drew 1-1*
Second replay - Villa Park - Chelsea won 5-1
1965/66- 4th round Stamford Bridge - Chelsea won 1-0
1966/67 - Semi-final Villa Park - Chelsea won 1-0
1969/70 - Final Wembley - Drew 2-2*
Replay - Old Trafford - Chelsea won 2-1*
* after extra time
Chelsea v Leeds in all competitions
Games played 101
Chelsea wins 33
Leeds wins 39
Biggest win at Elland Road for each team
Leeds 0-2 Chelsea - 24/09/1988 (Div 2), 28/11/2001 (League Cup)
Leeds 7-0 Chelsea - 07/10/1967
Visit again at lunchtime for Part Two of the briefing.