Surrey 144 for 7 (Roy 52) beat Worcestershire 142 for 9 (Peterson 2-12) by three wickets
Scorecard and ball-by-ball details

For the sixth time in 12 seasons, Surrey have made their way to Finals Day, this time at the expense of Worcestershire. The scorecard suggests the game was close but, as Surrey captain Gary Wilson admitted at the end of the game, they made it hard for themselves. Victory with 21 balls to spare tells it better than the three wickets in hand.

Surrey were favourites going into the game. At the halfway stage, those odds had shortened with the hosts needing 142 for victory - small fry, here, where all six targets under 160 have been chased with ease this season (Surrey responsible for five, Middlesex the other, when they adopted The Oval for a 'home' game against Somerset).

After five overs, with 64 on the board, 52 from the bat of Jason Roy, off just 20 balls, all bets were off. As well as Jack Shantry and Joe Leach bowled to peg things back, with figures of 2 for 26 and 2 for 22 respectively, it was only a succession of Surrey middle order brain fades that gave them a chance.

Kevin Pietersen looked like he would see things through, going along at a run a ball - above the rate required. But, once he failed to clear mid-off and Rory Burns was run out brilliantly by Brett D'Oliveira three balls later, panic set in. Three overs later, Azhar Mahmood top-edged to fine leg before Zafar Ansari was surprised by some bounce from Colin Munro to leave them needing another 14 with three wickets remaining.

Who knows how close things would have been without Roy's barrage. Regulars at The Oval will be familiar with his ability to thump through the line and drive along the practice squares, all while maintaining a solid base and fluid follow-through. They were treated to a new trick here, when he swapped hands and somehow managed to hit Shantry over square leg for a once-bounce four. Shantry stood there, mid-pitch, more in annoyance than awe, before meeting Roy's gaze and furrowing his brow. His half-century came up with a straight six - his third maximum in a boundary count that also included eight fours.

It was down to Robin Peterson to see Surrey home, keeping his head to close out the game with a six over midwicket and a nicely timed drive through mid-off.

Worcestershire were far from reckless in their innings but the approach of keeping dot balls to a minimum early on was ballsy; tip and run against arguably the best in-fielding side in the competition was always going to result in casualties. Sadly for them, it was Daryl Mitchell, captain and leading run scorer, who succumbed to it. Having lapped Jade Dernbach around the corner, he kept his eyes on the ball as it arrived on the bounce to Matt Dunn, before turning to look at his partner Richard Oliver, who had already made it halfway. Dunn's throw was near perfect; Dernbach finished it off and Worcestershire were 19 for 1 after three overs.

Surrey's bowlers rarely ceded control, pegging the opposition back after every moment of resistance. When Ross Whiteley used his sharp bat speed to hit Gareth Batty for four and six, he was bowled the next ball, eliciting the usual vein-popping scream from Batty. Joe Leach thumped Dunn over square leg for six and inside out through cover for four as 14 runs came off the 16th over, before he was embarrassed by a slower-ball from the back of Dernbach's hand that dipped under his mistimed hack across the line and on to the base of his off stump.

Oliver's 34, at less than a run a ball, featured two fours - though not for want of trying. He fell swinging across to line to one of the few loose balls he received: a short one from Peterson, which surprised him with a lack of bounce.

The pick of the Surrey's attack was Dunn, who served up four overs of the sort of pace that had you wincing on the edge of your seat. Touching 90 mph, his second wicket left one of Ben Cox's stumps standing. It was so savage that the ground needed repairing before the stumps could be reassembled.

Along with Roy, Dunn is another that has had England scouts asking after his performances. This has been a brighter season for Surrey than many expected. Sitting second in Division Two and now with a second consecutive appearance at Finals Day for their diary, they will go to Edgbaston as the most exciting and destructive team of the T20 Blast.