Prepare to be enthralled:
Jonny Evans' own-goal had given the Blues an undeserved half-time lead, but strikes early in the second period from Juan Mata and David Luiz had seemingly extinguished any hopes United had of closing the gap on Manchester City at the head of the Barclays Premier League table.
However, Wayne Rooney clinically converted a pair of penalties midway through the second period, before the champions' trademark spirit yet again bore fruit as substitute Chicharito headed home a leveller with five minutes of normal time remaining.
A dramatic afternoon was spared a last-gasp winner solely because of the brilliance of David De Gea, who made two stunning injury-time saves to give United tangible reward and keep the Reds within two points of the league leaders.
The Spaniard returned to action after injury, as did Rooney and Ashley Young; giving Sir Alex Ferguson a rare upper hand in the injury stakes against a Chelsea side bereft of John Terry, Frank Lampard and Ramires, while Ashley Cole and Didier Drogba were absent through suspension and international duty respectively.
Despite their absentees and apparent transition under the stewardship of Andre Villas-Boas, the Blues' September showing at Old Trafford, in which they were unfortunate to suffer a 3-1 defeat, warned against underestimating the former champions.