Saturday's fixtures in the fourth round of the 2014/15 FA Cup provided a number of logic-defying results around the UK.
Premier League leaders Chelsea were dumped in emphatic fashion by League One side Bradford City who produced a stunning 4-2 win at Stamford Bridge.
The Bantams fell behind by two goals after Gary Cahill and Ramires had netted by the 38th minute but Phil Parkinson's men fought back to claim a spectacular triumph thanks to goals from Jon Stead, Filipe Morais, Andy Halliday and Mark Yeates.
Reigning top flight champions Manchester City also me their demise in the form of Championship club Middlesbrough with Patrick Bamford, on loan from Chelsea, and Kike on target at the Etihad Stadium.
Crystal Palace fashioned a 3-2 come-from-behind win over Southampton after conceding to Graziano Pelle in the ninth minute before Marouane Chamakh responded two minutes later.
Scott Dann's 16th-minute own-goal had the Saints ahead once more but a debut goal from Arsenal loanee Yaya Sanogo preceded Chamakh's winner six minutes before the break to send the Eagles through.
Second tier side Blackburn Rovers got the better of Swansea City 3-1 at Ewood Park after falling behind to Gylfi Sigurdsson's opener with Chris Taylor, Rudy Gestede and Craig Conway all on target.
Leicester City also came from behind in their 2-1 win over Tottenham at White Hart Lane with second-half goals from Leonardo Ulloa and a very late winner from Jeffrey Schlupp overrding Andros Townsend's 19th-minute penalty.
In the late game, Bolton forced a 0-0 draw with Liverpool at Anfield to land a home fixture against the Reds which will take place alongside the other replays on February 4 and 5.
Elsewhere, Darren Bent hit the back of the net as Derby County defeated Chesterfield 2-0, Victor Anichebe snagged a brace in West Bromwich Albion's 2-1 win at Birmingham City, Reading edged Cardiff City 2-1 at the Madejski Stadium while Preston North End drew 1-1 with Sheffield United and Sunderland and Fulham played out a scoreless stalemate to set up replays.
Friday night saw League Two outfit Cambridge United hold Manchester United to a 0-0 draw which gives the U's the chance to take on the Red Devils at Old Trafford.
Sunday's fixtures see Bristol City hosting West Ham United, AFC Bournemouth at Aston Villa, Arsenal away to Brighton & Hove Albion prior to Monday's clash between Rochdale and Stoke City.
2014/15 FA Cup - 4th round scores
Chelsea (PREM): 2 (Gary Cahill 21', Ramires 38') Bradford City (L1): 4 (Jon Stead 41', Filipe Morais 75', Andy Halliday 82', Mark Yeates 90+3') Stamford Bridge, London - 41,014
Blackburn Rovers (CHA): 3 (Chris Taylor 23', Rudy Gestede 78', Craig Conway 89') Swansea City (PREM): 1 (Gylfi Sigurdsson 21') Ewood Park, Blackburn - 5,928
Cardiff City (CHA): 1 (Kenwyne Jones 25') Reading (CHA): 2 (Oliver Norwood 64', Hal Robson-Kanu 88') Cardiff City Stadium, Cardiff - 11,750
Birmingham City (CHA): 1 (Jonathan Grounds 45+1') West Bromwich Albion (PREM): 2 (Victor Anichebe 25'/35') St Andrew's, Birmingham - 28,438
Preston North End (L1): 1 (Paul Gallagher 19') Sheffield United (L1): 1 (Diego De Girolamo 68') Deepdale, Preston - 10,770
Southampton (PREM): 2 (Graziano Pelle 9', Scott Dann (og) 16') Crystal Palace (PREM): 3 (Marouane Chamakh 11'/39', Yaya Sanogo 21') St Mary's Stadium, Southampton - 31,320
Tottenham (PREM): 1 (Andros Townsend (p) 19') Leicester City (PREM): 2 (Leonardo Ulloa 83', Jeffrey Schlupp 90+2') White Hart Lane, London - 35,548
Sunderland (PREM): 0 Fulham (CHA): 0 Stadium of Light, Sunderland - 22,961
Derby County (CHA): 2 (Darren Bent 20', Will Hughes 82') Chesterfield (L1): 0 iPro Stadium, Derby - 28,392
Manchester City (PREM): 0 Middlesbrough (CHA): 2 (Patrick Bamford 53', Kike 90+3') Etihad Stadium, Manchester - 44,836
Liverpool (PREM): 0 Bolton (CHA): 0 Anfield, Liverpool - 43,847
