What happened? It was an all top-flight clash in the third round between Nottingham Forest and Manchester United and the visitors triumphed, thanks to a header from Mark Robins.
Why is it remembered? Alex Ferguson had been in charge of United for three years and had failed to win anything. In January 1990, some of United's supporters wanted him out of the club and it is believed that a loss against Forest would have seen Ferguson sacked.
The rest is history. United went on to win the FA Cup that season. They also, under Ferguson, became English champions 13 times, won four more FA Cups, the League Cup four times, the Champions League twice, the European Cup Winners' Cup once and the Fifa Club World Cup once.