Surrey 154 for 9 (Roy 78, Milne 3-26) beat Kent 144 for 8 (Denly 40, Clarke 4-16) by 10 runs
For the second night running Surrey held their nerve in a low-scoring NatWest T20 Blast thriller to land a 10-run over Kent that secured their place in the knockout stages and sent their opponents out.
The win, Surrey's seventh in an extremely tight South Group, was in doubt through to the final over when Rikki Clarke bagged three Spitfires wickets for only four runs to inflict Kent's seventh defeat. With their third successive victory, powered with the bat by Jason Roy's explosive 78, Surrey also secured a home quarter final while Kent missed out on the last eight for the second season running.
In pursuit of Surrey's 154 for 9, Kent's first-wicket partners Joe Denly and Daniel Bell-Drummond - fresh from their previous night's world-record T20 opening stand of 207 against Essex - initially took a slightly more measured approach.
Denly drove straight to the ropes off Jade Dernbach and Bell-Drummond cut wide ones from Sam Curran through to the boundary boards at extra cover. But when Curran dropped short, Bell-Drummond rocked back to hit a brace of sixes over midwicket.
With Kent's total on 39 Bell-Drummond played across a clever Dernbach slower ball to go lbw, but Denly glanced for four against Dernbach and drove through extra off Clarke to help Spitfires post 50 for 1 during their Powerplay.
Denly changed his bat to crunch a length ball from Stuart Meaker through the covers then Sam Northeast cut one through the legs of Jason Roy at backward point for another boundary.
Moises Henriques and Meaker stemmed the flow of boundaries and, with 78 on the board, Northeast's mistimed pull off Meaker was well held by Sam Curran at midwicket. Sam Billings strode in to take advantage of further sloppy Surrey fielding by hitting 11 off Meaker's next over, but Henriques pounced to bowl him via an inside edge as Kent fell behind the DLS rate for the first time.
Denly's stay ended for 40 when he edged an attempted steer against Clarke through to the keeper to bring together Darren Stevens and Jimmy Neesham with 56 still needed. They struggled initially before Neesham found his range by clipping a leg-side six off Dernbach to reduce the target to 26 but Stevens then nicked behind when cutting at Curran to give Surrey renewed hope.
With 15 needed off the last over the hugely experienced Clarke caught-and-bowled Alex Blake, had Neesham caught on the deep midwicket ropes and snared Adam Milne lbw with a slow full toss to break Kentish hearts and end the game with stunning, four-over figures of 4 for 16.
Fielding first after losing the toss, Kent made an immediate tactical switch by opening the bowling with left-arm spinner Imran Qayyum, who conceded only seven - including Aaron Finch's first six of the night over backward square.
Kiwi allrounder Neesham conceded a brace of boundaries to Roy in the second over, then his countryman Adam Milne suffered similar punishment as 15 came off over three. Having already changed his bat twice, Roy launched his first six into the pavilion in the fourth over from Mitch Claydon as 12 came off the over, but Finch's involvement ended when he played on when attempting a back-foot force off Milne.
Milne's next delivery, a shooting offcutter, trapped Henriques lbw. Ben Foakes survived Milnes' hat-trick delivery but, with two quick wickets in the bag, Kent slipped Qayyum back into the attack for the final Powerplay over that ended with the visitors on 59 for 2.
Roy moved to his 26th T20 fifty from 31 balls with a straight six off Stevens as Surrey reached 98 for 2 at the innings mid-point. Claydon returned to have Foakes well caught low down by Qayyum at mid-off but Roy cantered on, moving to 78 with an impudent flick over third man off a Calum Haggett. After clubbing 10 fours and four sixes, he then miscued to deep midwicket.
Curran and Ollie Pope both struggled against the extreme pace of Milnes and the tenacity of Haggett and Claydon. Surrey's fifth-wicket pair mustered only 19 before Pope was bowled when aiming an audacious lap over the keeper's head to give Haggett creditable figures of 2 for 32.
Clarke holed out to mid-off against Neesham who, three balls later, picked up Rory Burns off a skier to extra cover to finish with 2 for 26. Milne switched ends for the last over to skittle Curran off an under edge and finish with 3 for 26 as Surrey set Kent 155 to win at a rate of 7.75 an over on a tricky pitch.