Worcestershire 137 for 5 (Ferguson 64*) beat Gloucestershire 136 for 8 (Hammond 45, Cockbain 35, D'Oliveira 4-26) by five wickets

And then there was one. Worcestershire reached a T20 Finals Day for the first time when they made short shrift of Gloucestershire, scraping through by five wickets with seven balls to spare. Now only Derbyshire, among the 18 first-class counties, have never made it to what has become county cricket's end-of-season knees-up, further emphasis of the competitive nature of England's professional circuit.

Never mind a knees up, without the skill and composure of Callum Ferguson Worcestershire might have gone boomps-a-daisy. Ferguson's unbeaten 64 from 47 balls babysat the Blast's youngest squad through to Edgbaston. Adelaide born, and like much in that charming city, relatively undervalued, he has been one of the stars of the county season.

Michael Klinger, Gloucestershire's captain, knew their mediocre 137 for 5 was vulnerable to one quality innings. "We didn't bat well enough," he said. "No one took responsibility like Callum Ferguson did for Worcestershire, guys getting 20 and 30 and not going on including myself. We didn't get a big enough total."

By the time within the first four overs that Worcestershire lost Moeen Ali (like Jos Butter for Lancashire two days earlier, an England player introduced with no magical effect) and Joe Clarke with only 25 on the board, Ferguson was exploring a shrewd drive or two. When they faltered again at 66 for 4 - the 11th over in play, Benny Howell having trapped Brett D' Oliveira and Ben Cox with unnoticed changes of pace, he had bristled with authority square of the wicket. Whatever met him, he dealt with it.

Ferguson's assessment even included an uplifting message about the value of club cricket. He was asked on Sky Sports about recognising the need to bat through the innings. "I reckon playing league cricket when I was younger helped with that sort of thing," he said. "We have a lot of talented strikers in the side." A man who respects the game - at all its levels.

The game was broken in the 16th over. David Payne went for 22 in an 11-ball over which included two no balls, two wides and a free hit. Just by standing there, and looking as if he was about to unload against anything in his arc, the dangerous Ross Whiteley caused consternation. During the lifetime of this over, Whiteley struck two sixes, the first of them a remarkable stooping straight flick off a low full toss. A high full toss had hit him in the stomach but only served to sharpen his appetite.

A rickety old ground on a flood plain, capable of cramming in around 5,000 spectators: Worcestershire are a world away from the ECB's future vision of global short-form entertainment on the biggest international grounds. But now they have joined Lancashire and Sussex on what has the makings of a memorable climax at Edgbaston on September 15. Somerset and Notts contest the final place at Taunton on Sunday.

The Rapids had another matchwinner. "Some good ones, some bad ones." So said D'Oliveira about his spell of 4 for 24, becoming the latest legspinner to have a field day in the Blast, and one of the most unsung leggies in the tournament. D'Oliveira, a diminutive figure with an air of cheery innocence, adorned a season where he had taken only four wickets in 12 matches in the group stages.

When he took his fourth wicket with a rank long hop, silencing Jack Taylor, Gloucestershire's last hope of plotting an escape, with a ball that scuttled through at knee high, D'Oliveira held his hands to his face in a similar manner to Stuart Broad when he took eight Australian wickets in a morning session three years ago. Replace Broad's amazement with a little more good-natured mischief and you get the idea.

Alongside D'Oliveira, Daryl Mitchell was an effective sidekick. He did not concede a single boundary in a spell that conceded only 15 and also claimed Gloucestershire's first wicket, that of Miles Hammond, whose 45 from 31 balls had energised an opening stand of 65 from 7.4 overs.

Pat Brown, the 20-year-old seamer who has found himself the Blast's leading wicket-taker was seen off in one over; Moeen Ali dispensed with his own bowling in two. Klinger was subdued but Hammond's dash disguised it. Then Mitchell had Hammond lbw, sweeping, and the door was opened for D'Oliveira. Gloucestershire faded like colours under a tropical sun.

Klinger, feeling the pressure, shook his head philosophically and drove D'Oliveira down long-on's throat: Ed Barnard, a safe pair of hands. D'Oliveira trotted back from the stumps to clutch Benny Howell's slog sweep. Then came two devilish long hops - Ryan Higgins hauling to long on when he might have sixed him over midwicket, Taylor betrayed and bereft.

Barnard, an excellent fielder, ran out Ian Cockbain, who had reached 35 amid the chaos, 17 balls from the end, but even on a slightly tacky pitch few imagined that Gloucestershire had enough runs at the interval.