The record book - and its form equivalent - go out of the window in FA Cup games, apparently. That's just as well for Chelsea, because in 11 games against Manchester United in the competition they have won just twice - in 1950 and 2007.
Warning over, here are six clashes between the Reds and the Blues.
MANCHESTER UNITED 2-0 CHELSEA, 1988 FOURTH ROUND
Rejuvenated under Alex Ferguson, United would finish second in that season's Division One behind Liverpool but ended a third straight campaign trophyless despite progressing past Chelsea in January's cup tie.
Brian McClair, who would become the first United player to hit 20 league goals since George Best, had a penalty saved by 19-year-old goalkeeper Roger Freestone but was spared when Norman Whiteside stooped to put United ahead.
McClair then did get his 19th goal of the term when he tidily finished past the teenager in front of the Stretford End.
MANCHESTER UNITED 4-0 CHELSEA, 1994 FA CUP FINAL
One of the most deceiving scorelines in Cup final memory, although United were favourites having just won their second successive Premiership title under Alex Ferguson, Chelsea had done the double over them in the league. Gavin Peacock, now a Christian pastor, had scored the only goals in wins for the Blues at Stamford Bridge and Old Trafford, and lightning almost struck thrice at Wembley when he smacked Peter Schmeichel's crossbar in the first period.
Chelsea were the better side but after the pause they capitulated. Eddie Newton's outrageously timed tackle led to a penalty, which Eric Cantona converted to break the deadlock before David Elleray, ironically loathed by United fans, awarded the Reds an erroneous spot-kick after Frank Sinclair bundled Andrei Kanchelskis to the ground. Dennis Wise approached Cantona prior to take two and bet him £100 he wouldn't score. Cantona placed the ball in exactly the same corner and sent Dmitri Kharine the wrong way again.
Mark Hughes, who would win his fourth FA Cup with Chelsea in 1997, made it three before Brian McClair added gloss, following selfless work from Paul Ince, to clinch United's first domestic double in their history.
CHELSEA 1-2 MANCHESTER UNITED, 1996 SEMI-FINAL
The Wembley pitch harmed the quality of a later cup match between the sides (more of that later) but at least the grass was visible. Villa Park resembled a sand pit - pre-dating Chelsea's own 'sand pitch' win against Charlton by seven years - for the first of the day's semi-finals.
A terrific match despite the appalling surface, the woodwork was rattled thrice in the opening 45, with only Ruud Gullit hitting the back of the net from Mark Hughes' cross.
United however rallied in the second 45. The excellent Phil Neville's cross was eventually headed back by Eric Cantona for a grateful Andy Cole to equalise, before Craig Burley's inexplicable back pass was intercepted by a composed David Beckham to pass the winner past Kevin Hitchcock, send Reds into a frenzy. For the third consecutive year, United were going back to Wembley.
CHELSEA 3-5 MANCHESTER UNITED, 1998 THIRD ROUND
Under Ruud Gullit, Chelsea were considered title challengers for the first time in decades ahead of the 1997-98 season. Marcel Desailly, Celestine Babayaro, Tore Andre Flo, Bernard Lambourde and Ed de Goey joined a club brimming with continental flair after Italian trio Gianluca Vialli, Gianfranco Zola and Roberto di Matteo signed the previous summer. But in the standout third-round tie, they were humiliated by a predominantly British United.
David Beckham half-volleyed Teddy Sheringham's flick-on for the opener - prompting one of his more memorable celebrations - before curling in a precise free-kick, with Sheringham subtly creating a gap in Chelsea's flimsy wall. Andy Cole made it 3-0 before the pause with an excellent solo strike.
Cole dashed any hopes of a Chelsea comeback quickly after the re-start before Sheringham made it an astonishing 5-0. Chelsea had only lost once all season at Stamford Bridge, when Arsenal emerged victorious thanks to Nigel Winterburn's uncharacteristically spectacular late winner in September.
A classy Graeme Le Saux chip and two Vialli goals unsettled some United fans in the last 10 as the team's concentration dipped, but the consolations served only to flatter the hosts.
CHELSEA 0-2 MANCHESTER UNITED, 1999 QUARTER-FINAL REPLAY
Dwight Yorke's reputation as a womaniser, like the Brazilian Ronaldo's for being fat, should not mask his brilliance on a football pitch. Yorke had the season of his life when United won the Treble and his ingenuity was perhaps best expressed at Stamford Bridge.
The original match at Old Trafford ended 0-0, with Gary Neville hitting a post after surging forward and a couple of harsh red cards for Roberto di Matteo and Paul Scholes the only incidents from a drab game on a dreary day. Three days later, Yorke lit up a nocturnal Stamford Bridge with a masterful brace.
The first, an underrated half-volley, led to the lamentable baby-rock celebration six days after the birth of Brooklyn Beckham. But the Trinidad and Tobago striker later made amends with a magnificently surprising chip over Ed de Goey from outside the area, cementing his status as one of the best attackers in Europe.
CHELSEA 1-0 MANCHESTER UNITED, 2007 FA CUP FINAL
If the previous year's FA Cup final was the best in living memory this was the worst. Both teams' treble chances were alive with five games of the season remaining but had both been eliminated at the Champions League semi-final stage. Despite a growing injury list United saw off Chelsea for their first league title in four years and denied José Mourinho three in a row, but come cup final day both squads were physically drained.
The first final at the new Wembley, the pitch - often maligned when the original hosted the showpiece occasion - made it a turgid affair. It was the era of the Big Four, when matches were often won by the odd goal amid chess-like tedium that sold football as well as The Simpsons. Jorge Valdano memorably described Liverpool's approach during as "s**t on a stick" football.
After a goalless 90 minutes Didier Drogba naturally struck for the third final goal of his Blues career to settle 120 stultifying minutes.