Edgbaston will be full for a Finals Day that promises to show some of the game’s less heralded sides at their Twenty20 best

Surrey have already been crowned county champions, England have wrapped up a Test series victory over India and the football season is back in full flow. Now, three weeks after the Vitality Blast’s quarter-finals, Somerset, the Worcestershire Rapids, Lancashire Lightning and the Sussex Sharks descend on Birmingham on Saturday for Finals Day.

Despite this year’s announcement about the contentious new 100-ball tournament from 2020, the Blast has drawn a record aggregate attendance of 931,000 to matches. The season’s distended scheduling might mean that some key overseas signings are unavailable on Saturday but the Blast, once the poor relation of Twenty20 leagues such as the Indian Premier League and Australia’s Big Bash, has turned itself into something of a success story. This year Edgbaston announced before the competition had even begun that it had sold out its 24,550 capacity for Finals Day.

The quality of cricket has been lauded too. By the end of this year’s league stage, the Blast’s overall run rate was 8.88 runs per over; not only is this the best scoring rate in the history of the tournament but also compared to any other domestic Twenty20 league globally.

In a two-fingered salute to the structural tinkering, the day also features some of the less fashionable counties. Of the four teams present only one, Lancashire, are based at a ground that has been announced as a base for a new franchise team in the proposed 100-ball tournament. The other semi-finalists are instead counties who have built up almost cult-like followings through their Twenty20 campaigns.

Somerset embody this in particular; their opening batsman Johann Myburgh, who plays exclusively white-ball cricket for the county and announced his retirement at the end of the season, was given a standing ovation at Somerset’s final home match. In four seasons the South African has become what many thought was an oxymoron: the popular Kolpak.

The gruelling schedule of Finals Day, in which two semi-finals are followed by the final later in the evening, has always made things unpredictable, something the shorter format lends itself to anyway. Predicting the outcome on this occasion however feels particularly tumultuous because, despite the Blast being the fastest scoring competition in the world, in three of this year’s quarter-finals the side batting first misread conditions on slower pitches. The spin attacks in particular have proved a huge asset to all four sides.

The Sussex captain, Luke Wright, believes the left-arm spinner Danny Briggs is an underestimated quantity, moreover, his performances to date overshadowed by the much vaunted pace trio of Tymal Mills, Jofra Archer and Chris Jordan.

The nature of the scheduling means that while the pitch might be high scoring at first, it will likely get lower and slower as the day wears on. Should Lancashire, who play first against Worcestershire, reach the final this could fall in their favour as 52% of the overs they have bowled in their campaign so far have been spin, far more than any other team.

Somerset, who face Sussex, inch in as favourites, their deep batting lineup and potent mixture of seam and spin producing a nicely balanced side. Not only did Somerset finish the league stage with the most points, they knocked out last year’s winner, Nottinghamshire, along the way.

“I’ve learned a lot throughout the competition,” Somerset’s new white-ball captain, Lewis Gregory, said on Friday. “And I’m lucky there are some very experienced guys around me to help with that. It’s been really nice to have that [responsibility] put on me.” Batting at No 7 he has a strike rate of 217, which exceeds all others, has faced the fewest dot balls of any batter and hits a boundary every 3.14 balls.

Worcestershire, alongside Derbyshire, are one of two counties never to have featured in a Finals Day, so they go into today with plenty to learn and little to lose and much to gain. So enthralled are they to have got this far that Joe Leach, their injured captain, has packed his kit in preparation for a “full-kit John Terry” appearance should his teammates win the trophy.

And Daryl Mitchell, asked if he had the choice between surviving relegation in the County Championship (currently unlikely) and winning the Blast, opted for the latter. Test cricket showed this summer that it still has the capacity to captivate an audience; perhaps domestic Twenty20 can too.