Surrey 181 for 7 (Finch 61, S Curran 39, van der Merwe 3-27) beat Somerset 177 for 9 (Anderson 81) by four runs
An explosive 81 from 45 balls by Corey Anderson, with seven sixes and three fours, and a dramatic 12-run penalty, could not prevent Surrey from squeaking home by four runs in a remarkable Nat West T20 Blast match at the Kia Oval.
Led by stand-in captain Jade Dernbach, Surrey go top of the embryonic South Group table with two wins from two games, with the run out of Anderson in the final over the key moment in a game which had seemed all over before the award of penalty runs with three overs remaining because of an illegally slow overrate.
Dernbach spoke afterwards about the 12-run penalty, actioned by umpires David Millns and Paul Baldwin, who judged Surrey two overs short of their allocation within the time limit.
He said: "To be honest I was pretty much in the dark out there about the possibility of a run penalty. It was the first I heard of it when it was given. But these things happen and you have to take it on the chin.
"I'm just a little puzzled because on Friday night, when we played Essex at Chelmsford and the game was on TV, there seemed to be a little bit more leeway.
"But it was crucial to get Corey Anderson out in that final over, because he had played unbelievably well, and then Tom Curran held his nerve again at the death, as he did in that Essex match. I'm so proud of him and happy to see him performing like this in big pressure situations."
Dernbach shot out Jim Allenby and James Hildreth for first ball ducks in a superb opening over, which ended with Somerset 1 for 2 in reply to Surrey's 181 for 7, in which Australian batsman Aaron Finch hit 61 from 42 balls with three sixes and seven fours.
Somerset eventually made it to 177 for 9 thanks to some magnificent hitting from New Zealand all-rounder Anderson, who struck Tom Curran for successive sixes at the start of an 18th over which, before the penalty runs were added, had begun with 51 needed.
Suddenly, the equation was down to 23 from two overs, and Anderson ramped up the excitement by flicking Dernbach over mid wicket for six in the 19th over. But then, after a four to mid wicket and attempting a two to long on, Anderson failed to bet Finch's throw to the keeper. Curran then held his nerve to allow just two runs from the final three balls at Somerset's last pair.
Somerset captain Jim Allenby revealed that Anderson had suffered a stiff back after bowling the first over of the game, which is why he later left the field for treatment and could then only come into bat at No 7.
Allenby said: "He's been flying a lot around the world recently, so we just wanted him to take it easy and not make it worse - especially right at the start of the tournament. When he comes in at No 5, which he should in future games, he will give us even more firepower and especially if we bat better as a team.
"Today, those of us at the top of the order let us down because we made a terrible start. But Corey's was a special innings and it deserved to win the game. If we had batted better up front, it would have been a match-winning innings."
Besides Finch's fine effort, Surrey's total also owed much to their two 19-year-olds, Sam Curran and Ollie Pope, who played some spectacular strokes of their own in quickfire innings of 39 and 25 not out respectively.
It was then the turn of Sam and Tom Curran, with the ball, and well-supported by fellow seamer Ravi Rampaul, to further undermine the Somerset innings and leave it in tatters at 49 for 6.
A crowd of more than 15,000 lapped it up as Tom Curran had Steven Davies leg-before for 15 with his third ball, in the fifth over, before bowling Peter Trego for 10 in his next over. By then Rampaul had dismissed Adam Hose for 5, caught at short fine leg, and soon afterwards Sam Curran returned for a second spell to pin Roelof van der Merwe leg-before for 10.
Rampaul had Lewis Gregory caught on the cover ropes for 6 in his second spell and Craig Overton (11) offered a blow or two in support of Anderson before swiping a Sam Curran full toss to deep mid wicket.
Surrey's innings was given a flying start by Finch and Jason Roy, who took 45 from the first four overs. Roy, who had clubbed Craig Overton to long on for six, swished his bat in annoyance after pulling Josh Davey straight to deep mid wicket for 15 in the fifth over but Finch continued to attack and the initial powerplay ended with Surrey on 59 for 1.
Finch had warmed to his task by plundering two fours and a pulled six from the first three balls of the third over, bowled by Davey, and then took two offside fours from Roelof van der Merwe's second over before swatting Max Waller's first ball to wide long on for another six.
Mark Stoneman chipped van der Merwe to extra cover to go for 8 but, at halfway, Surrey were 92 for 2 and on course for a 200-plus total. That ambition looked less likely when Finch, after a third six driven wide of long on off van der Merwe, hit the same bowler to Lewis Gregory on the long on boundary three balls later.
Rory Burns went cheaply but Sam Curran, with a competition-best 39 from 21 balls, with two sixes and four fours, did his best to keep up the tempo. He was particularly dismissive of Waller's leg spin, driving him straight and then pulling him for sixes in the space of three balls in a 14th over costing 19.
Dom Sibley could not quite clear Adam Hose at deep square leg when, on 7, he scooped a full toss from van der Merwe high into the South London sky, but the younger Curran's invention saw him flip Overton for a cheeky four past the keeper from way outside his off stump, besides crunching fours through extra cover and mid wicket with more conventional strokes.
Curran squeezed a full, wide ball from Davey to cover - which would have surely been called a wide if he had left it - before Pope hit a jaunty unbeaten 25 in the closing overs, including two wonderfully-manufactured deflections to the fine third man boundary and a cracking square driven four off Overton. Tom Curran made 8 before being caught at mid wicket from the final ball of Surrey's innings.