There may have been talk of a lack of FA Cup shocks after Saturday's Third Round day but Sunday provided the big story the competition always craves. League One's Leeds United rolled back the years and defeated Manchester United at Old Trafford, a stadium they had not won at since 1981.
And it was Jermaine Beckford who followed in the footsteps of Brian Flynn 29 years ago with a 19th minute strike. The physical striker, who made a nuisance of himself all afternoon, seized on a long ball to bissect Gary Neville and Wes Brown and flick the ball beyond Tomasz Kuszczak. Thereafter, the home side pushed for a goal that would not come, with Dimitar Berbatov and Michael Owen both guilty of misses, with Owen's shank with the goal gaping the most glaring, but Leeds were the deserved winners and could have had more with Beckford missing a second-half chance to double his haul and Robert Snodgrass rattling the angle of bar and cross with an unerring free-kick.
Sir Alex Ferguson bristled in annoyance while Simon Grayson, a lifelong Leeds fan who now manages his beloved team, celebrated a victory that may soothe the years of hurt fallen giants Leeds suffered in the decade just gone.
No such problems for holders Chelsea with an opponent from a lower division. Watford were soundly thrashed 5-0 at Stamford Bridge, with Daniel Sturridge scoring twice, his first Blues goals. His twin strikes bookended an own-goal from John Eustace, Florent Malouda and Frank Lampard.
Arsenal looked for as though they would be exiting the tournament at the first hurdle as West Ham United had taken a lead through Alessandro Diamanti. But a second-half surge from the Gunners saw them progress thanks to two late and quickfire goals from Aaron Ramsey and Eduardo Da Silva to secure a 2-1 victory.
Wolves midfielder Matt Jarvis atoned for missing an open goal by scoring the winner in a hard-fought 1-0 victory over League One Tranmere Rovers at Prenton Park.
The FA Cup third round tie looked to be heading for a replay until Jarvis latched on to a Nenad Milijas through-ball and hit a first-time shot past Luke Daniels 13 minutes from time to secure a fourth round meeting with Crystal Palace.
Into the draw for the next round go both Queen's Park Rangers and Sheffield United, after a 1-1 draw at Bramall Lane, with Blades' Richard Cresswell cancelling out a Jay Simpson strike.
Notts County's tie with Forest Green Rovers was called off due to an excess of wintry conditions so Sven Goran Eriksson's Magpies must wait to play their non-league opponents.