One-day kings Gloucestershire were beaten at the knockout stage of a cup competition for the first time in three years as Durham defeated them by three runs in a thrilling finish to the fourth-round tie at Bristol.
Gloucestershire's glorious run had stretched back to July 8, 1998, when Surrey were victorious over them in a NatWest Trophy second round match.
But hopes of a 20th successive win were ended when they failed to get the nine runs required off the last over, as they finished on 229-9 in reply to 232 all out.
A fourth-wicket stand of 74 between Matt Windows (56) and Chris Taylor (32) appeared to have put Gloucestershire on course for victory.
But a requirement of 54 from the final ten overs proved out of reach as rookie left-arm spinner Graeme Bridge and pace bowlers Mark Davies and Danny Law came up trumps for Durham.
Bridge, who had only played for the Durham Board XI previously in the competition, claimed the man-of-the-match award for his 3-44.
Durham captain Jon Lewis said: "This is a very proud moment for us. Gloucestershire have a tremendous record here at Bristol and have set the standards in one-day cricket.
"I was quite happy with 232 and although our bowling looks inexperienced, they did very well today."
Durham, who were put into bat by Alleyne, reached 100 in the 20th over before being pegged back in the closing stages of their innings.
Paul Collingwood hit six fours in his 38 before being caught behind by Jack Russell off James Averis, one of four wickets for the Gloucestershire paceman.
But Lewis ensured that his side still reached a respectable score with an unbeaten 65 from 99 balls, with just two boundaries.