Sam Curran and Dominic Sibley combined to send Surrey to Vitality Blast finals day.
The pair cracked 95 from 63 balls to ensure Durham were beaten by five wickets with two overs to spare to qualify for finals day at Edgbaston on Saturday (September 14).
Director of cricket Alec Stewart highlighted the competition as one of his targets at the start of his final season in charge and now Surrey must fight their way past holders Somerset in the semi-finals, having been beaten by them at the same stage 12 months ago. The winners of that match will play Sussex or Gloucestershire.
Surrey, who finished ahead all of them to win South Group, will be bidding to win the competition for the first time since 2003, the inaugural year of the competition.
It was the first time they had met Durham in a T20 match and, in front of a crowd of around 21,000 at the Kia Oval, it looked set to be a one-sided affair as the visitors slipped to 69 for six in the 13th over.
Taking advantage of winning the toss, Dan Worrall (two for 14) and Reece Topley (two for 20) found swing and seam assistance, backed by a brilliant direct hit run out from Curran which sent back Colin Ackermann.
Durham climbed back into the match, though, Michael Jones (37 not out) taking advantage of the ball going softer and Ben Raine’s 23 from eight deliveries principally responsible for 37 being extracted from the final two overs, being particularly harsh on the unusually wayward Chris Jordan.
A final total of 162 for eight was well in excess of expectations and threatened to be a winning score when Will Jacks (eight) and Laurie Evans (one) departed early in the reply.
It was 53 for three when Rory Burns (ten) followed but Sibley rarely looked in trouble and belied his reputation as the epitome of steadiness with a remarkable ramp shot over third man for six.
Curran, who scored a century earlier in the competition, took toll of the spinners with Nathan Sowter disappearing for an enormous blow into the crowd, one of the left-hander’s four sixes.
The pair were finally split in the 17th over when Sibley was bowled by Callum Parkinson for 64 off 48 balls, which included six fours and two sixes. Curran took Surrey within three runs of victory, trapped leg before wicket by Raine for 52 from just 34 deliveries, but by then the match was won.
“We weren’t happy with the way we finished in the field,” admitted Jordan afterwards.
“But if you’d given us 160 at the beginning, knowing how much better the pitch gets by the end, we’d probably have taken it.”
Surrey last reached the final in 2020.
Surrey drew against Nottinghamshire in Vitality County Championship Division One.
Skipper Rory Burns followed up his double-century against Lancashire with 161 against Nottinghamshire but the docile Trent Bridge pitch – and use of the Australian Kookaburra balls, which offer little help to seam bowlers – meant his side were always battling to add to their seven wins out of ten in the run-up to the match.
Ryan Patel (77) and Will Jacks (59) both enjoyed lengthy partnerships with Burns while Indian left-hander Sai Sudharsan, brought over to strengthen the batting, hit 105, his maiden century for the county.
Surrey just missed a fourth batting bonus point on their way to 525 all out and much of that had to do with off-spinner Farhan Ahmed. He took seven for 140 from 50 overs in the first innings and three for 77 in the second.
Their seamers neutered by conditions, Surrey had to rely on Jacks’ off-spin to bowl out the hosts for 405. Freddie McCann cracked an impressive 154 while Jack Haynes (68) and South African Kyle Verreynne (50) further delayed Surrey, Jacks finishing with seven for 129 from 43.5 overs.
While survival was relatively easy, scoring quickly was far more difficult, hampering Surrey’s hopes of setting up a declaration. Burns (71), Patel (21) and Sudharsan (28) pushed them to 177 for nine declared.
They set Notts 298 on the final afternoon, and the hosts batted out at 121-0 to collect 12 points to Surrey’s 13.
By Richard Spiller