Mexican footballer Javier Hernandez saved Manchester United's blushes as the Premier League leaders came from behind to defeat League One Southampton 2-1 to advance to the last 16 of the FA Cup.
Chelsea and Aston Villa are also through while the surprise of the day came from non-League Crawley Town beating Torquay while Brighton & Hove Albion and Leyton Orient also made the fifth round.
In a repeat of the 1976 final, Hernandez slid home a 75th-minute winner after a Michael Owen header for an under-strength United had cancelled out a stunning strike from Richard Chaplow which had given Southampton the lead just before half-time.
Holders Chelsea needed a late equaliser by Salomon Kalou to snatch a 1-1 draw with Everton at Goodison Park.
In another of the weekend's five all-Premier League ties Aston Villa beat Blackburn Rovers 3-1 in a repeat result of their third-round meeting a year ago. All their goals came in the first half from Ciaran Clark, Robert Pires, who won the Cup three times with Arsenal, and Nathan Delfouneso.
Leyton Orient, struggling at the wrong end of the third division League One, pulled off a second successive upset win when, having knocked out Norwich City away from home in the last round, they won 2-1 at Championship promotion-chasers Swansea.
Crawley became only the sixth minor league side to reach the fifth round, beating League Two or fourth division Torquay 1-0 at Plainmoor.
In other matches, Birmingham staged a dramatic fightback against midlands rivals Coventry to advance, recovering from 2-0 down to win 3-2 at St Andrews.
Burnley defeated Burton Albion 3-1 while Championship side Watford were stunned 1-0 at Vicarage Road by Brighton from League One.
League Two Stevenage, conquerors of Newcastle in the previous round, saw their hopes of an extended cup run extinguished by Reading, 2-1, while in the day's other meeting between two Premier League clubs, Bolton drew 0-0 with Wigan at the Reebok Stadium.
Three-time FA Cup winners Sheffield Wednesday advanced to the fifth round after recovering from a goal down to beat Hereford 4-1.