On paper, Crawley Town attempt the impossible at Old Trafford this evening when the non-league team take on Premier League leaders Manchester United.
But the FA Cup offers proof that every underdog has its day. Unlikely exploits in the competition's past have ensured some of the grandest and greatest have had days to forget against lesser competition.
Worcester City 2 Liverpool 1, January 1959
In retrospect, 1959 was a pivotal year in Liverpool's history. The appointment of Bill Shankly as manager transformed the club. Before then, however, came an unprecedented embarrassment as Phil Taylor's side were eliminated from the FA Cup by Worcester. Dick White's own goal sealed the greatest result in the Southern League club's history.
Colchester United 3 Leeds United 2, February 1971
Feared more than they were loved, admired grudgingly but not openly, Leeds United were a machine in the early part of the 1970s. They reached the FA Cup final in 1970, 1972 and 1973, but not 1971. The exception came when Division Four side Colchester United didn't just beat Leeds: courtesy of Ray Crawford (2) and Dave Simmons, they took a three-goal lead. Don Revie's side got two goals back, but it was not enough.
Hereford 2 Newcastle United 1, January 1972
It was not so much one shock as two. Hereford United, then a Southern League club, had already drawn 2-2 at St James' Park, before a replay that brought them immortality. Malcolm Macdonald put Newcastle United ahead but, on a quagmire of a pitch, Ronnie Radford levelled with a goal voted the greatest in FA Cup history, a 35-yard thunderbolt. Ricky George then scored the winner to eliminate the 1969 Uefa Cup winners.
Bournemouth 2 Manchester United 0, January 1984
Manchester United were FA Cup holders and, under the flamboyant management of Ron Atkinson, one of England's glamour clubs. Bournemouth were a nondescript Third Division side whose manager was best known for being a former teammate of Bobby Moore and Geoff Hurst at West Ham United. Yet Bryan Robson, Arnold Muhren and Norman Whiteside were sunk by goals from Milton Graham and Ian Thompson. It was a coup for the Bournemouth manager: a young Harry Redknapp.
Wimbledon 1 Liverpool 0, May 1988
They were in the same division, but were worlds apart nonetheless. "The Crazy Gang and the Culture Club," said commentator John Motson as Wimbledon's impoverished upstarts took on Liverpool's aristocrats. Yet the rough-and-ready approach prevailed: Lawrie Sanchez headed the Dons ahead, Dave Beasant became the first goalkeeper to save a penalty in the final (denying John Aldridge) and Wimbledon won.
Sutton United 2 Coventry City 1, January 1989
Two-thirds of the way into a 34-year spell of top-flight football, Coventry had rarely been more successful. The 1987 FA Cup winners were sixth in Division One when they headed for Sutton United, a Conference side who otherwise rarely rated a mention outside their native London. This time, however, they were national news: Tony Rains and Matt Hanlon scored the goals on the last occasion non-league triumphed over top flight in the FA Cup.
Wrexham 2 Arsenal 1, January 1992
Arsenal were the defending league champions, a team with a reputation for ruthlessness that seemed to make them immune to upsets. Wrexham were bottom of the Football League and soon trailed to an Alan Smith goal. Then expectations were confounded: the 37-year-old Mickey Thomas equalised with a wondrous free kick and, capping a dramatic finale, the 20-year-old Steve Watkin sent Wrexham through.
Stevenage Borough 1 Newcastle United 1, January 1998
Stevenage defeated Newcastle last month, but the greater shock occurred 13 years ago. Then, Boro were 15th in the Conference, while United had finished second in each of the two previous Premier League seasons. Alan Shearer was the most expensive player in England and he put Newcastle ahead in the third minute. But Giuliano Grazioli earned a replay for a Stevenage side with a combined cost of £30,000 (Dh179,000).
Manchester United 0 Exeter City 0, January 2005
If Crawley require any encouragement today, there is a precedent for non-league teams drawing at Old Trafford. Six years ago, that was precisely what Exeter City did in one of the more embarrassing afternoons of Sir Alex Ferguson's career. Eleven days later, the United manager pressed Ryan Giggs, Cristiano Ronaldo and Wayne Rooney into service at St James' Park. The latter pair scored to send United through. Eventually.
Burton Albion 0 Manchester United 0, January 2006
As was the case 12 months earlier, non-league opposition drew with United, earning a lucrative replay and financing promotion to the Football League (eventually achieved in 2009) in the process. And while Nigel Clough's side lost 5-0 the second time around, the initial stalemate came against a side who brought Rooney and Ronaldo off the bench.