Surrey 169 for 2 (Amla 73*, Roy 56) beat Kent 113 for 7 (Jacks 4-15) by 56 runs
Surrey marched confidently on to their first Finals Day appearance since 2014 with a comprehensive dismantling of Kent, an eighth successive win in the T20 format ensuring they will extend their season a little deeper into the chill of October at Edgbaston on Saturday. Surrey's total of 169 for 2 was built upon a century opening stand between Hashim Amla and Jason Roy and then Kent were scuttled by the bowling of Will Jacks, whose career-best 4 for 15 ensured the chase never really got going.
Kent's opening pair of England star Zak Crawley and the competition's leading run-scorer, Daniel Bell-Drummond, were both removed in Jacks' opening over and the supposedly part-time offspinner struck twice more in the first half of the innings to remove Joe Denly and Sam Billings. Only two Kent batsmen managed to score at above a run a ball, as Surrey's spinners tied them down effectively; Dan Moriarty and Gareth Batty each picked up a wicket apiece and Surrey's progression became a formality as the afternoon wore on.
Having not managed a win in any format through August, their resources hit by injuries and England call-ups, Surrey have subsequently found a formidable formula in the Blast and will fancy their chances of lifting the T20 trophy for the first since its inaugural season back in 2003.
Surrey's opening gambit
While a lack of first-team players hurt Surrey earlier in the season, a glut of options was their issue in selecting an XI for this quarter-final. Amla was available again after a calf problem, and he was recalled to join Roy in a new opening partnership for this competition. That they kicked off with a century stand ought to have been good news for the home side, but in a week in which the value of big partnerships in T20 has come into question, there was a nagging worry that neither was able to truly cut loose.
Roy, after a scratchy summer searching for form in the England bubble, compiled his second consecutive fifty - smartly enough, from 39 balls - but then got out when set. Having taken up 12.5 overs, the opening stand was a work of construction to compare with the new Peter May stand rising to one side of the pavilion, but it didn't leave long for those coming after to get in and crack on.
Jacks out of his box
The man shuttled out of position by the availability of Amla and Roy was Jacks, who opened in each of his nine previous innings on the way to a breakout season in this format. He hinted at what Surrey may have missed out on, striking driven fours from his seventh and eighth balls, then pulling his tenth for another boundary; but on a slow surface, used previously for the final group game between these two teams, both batsmen struggled to hit the afterburners during the closing stages, with Amla's flogged six over extra cover in the final over the only time Surrey managed to clear the rope.
However, while Jacks was not required at the top of the order with the bat, his role with the ball proved instrumental. Before this season, he had only previously sent down three overs of his offspin in T20 cricket, but this year he has regularly taken the new ball during the Powerplay. His opening over dealt a hammer blow to Kent's chances, with Bell-Drummond and Crawley both falling to smart Ben Foakes catches - a sweep that looped to leg and a thin outside edge respectively - and he then returned to take wickets in the eighth and tenth overs to effectively kill off the chase.
Kent chase their tail
A quirk of this year's three-division system meant that first and third in the South Group ended up facing each other in the quarter-finals. Kent and Surrey each won their home encounter during the group stage, both times chasing a target in the region of 160 - and that presumably informed Billings' decision to put Surrey in after winning the toss at the Kia Oval on a crisp, autumnal day. The fact that six of Surrey's seven consecutive wins had come while chasing was likely a factor, too.
Kent had included an extra bowler in their XI, with the economical Tim Groenewald coming in for Heino Kuhn, while Surrey had gone the other way, leaving out a seamer - and although the slow-and-steady approach of the opening pair carried an inherent risk, it soon became evident that a tacky surface would play to Surrey's strengths when it came to defending a target.
With Jacks and slow left-armer Moriarty delivering the first four overs, Surrey set out their stall to choke Kent early on. Ten of the first 14 overs bowled were sent down by the three spinners as Kent fell to 67 for 5 and saw their chances of progression slip away. In the end, such was the home side's dominance that "Surrey's Andre Russell", allrounder Jamie Overton did not bat and was only required to bowl one over while the game was in the balance.
Alan Gardner is a deputy editor at ESPNcricinfo. @alanroderick