Vitality Blast, The Kia Oval
Durham 162-8 (20 overs): Jones 37*; Worrall 2-14, Topley 2-20
Surrey 164-5 (18 overs): Sibley 67, S Curran 52; Carse 2-34
Surrey beat Durham by five wickets
Surrey overcame a fine Durham fightback to become the first team to make it to T20 Blast Finals Day.
Chasing 163 to win, a 95-run partnership between Dom Sibley (67) and Sam Curran (52) for the fourth wicket tipped the game in Surrey's favour from 53-3 and they wrapped up the win with two overs to spare.
After being put in to bat, Durham had a horror start, falling to 36-4 in the eighth over, before recovering superbly to post 162-8 at The Oval.
Michael Jones (37 not out) and lower-order cameos from Ashton Turner, Bas de Leede and Ben Raine gave the visitors a competitive total but it turned out not to be enough to prevent Surrey booking their spot at Edgbaston on 14 September.
Surrey's pace bowlers Dan Worrall (2-14) and Reece Topley (2-20) made early inroads into Durham's top order as they struggled to put runs on the board.
When Sam Curran's quick-thinking and expert arm ran out Colin Ackermann at the non-striker's end to leave Durham 61-5 at the halfway stage, the visitors looked to be in big trouble.
But the lower order fired and De Leede (24) and Raine (23) added quickfire boundaries, along with Jones' powerful striking, to give Durham something to defend.
Their own pace bowlers restricted Surrey early on in their reply, with Brydon Carse picking up the wickets of England's Will Jacks and Laurie Evans, before Rory Burns, batting at four, also departed cheaply.
But Sibley stayed put and it was his partnership with Curran which took the game away from Durham.
They both departed before the end, Sibley to the spin of Callum Parkinson and Curran to Raine, leaving Jamie Overton to hit the winning runs.
Wednesday: Sussex Sharks v Lancashire Lightning (19:00, Hove)
Thursday: Northamptonshire Steelbacks v Somerset (18:30, Northampton)
Friday: Birmingham Bears v Gloucestershire (19:00, Edgbaston)