Somerset 282 (Abell 82; Singh 5-72) and 265 for 4 dec (Trescothick 119*, Hildreth 68, Abell 51) beat Warwickshire 146 (Barker 52; Leach 5-50, Overton 4-33) and 232 (Trott 74, Groenewald 5-58) by 169 runs.
In the end, after a morning of frustration followed by a good many anxious skywards glances as a convoy of dark clouds loomed one after another over the roof of the pavilion, Somerset needed 85 uninterrupted minutes to finish the job and claim the win that had looked theirs for the taking ever since they won the toss, at once keeping their own survival prospects intact and killing off Warwickshire's, in realistic terms if not mathematically.
Dom Bess, whose penultimate over on Thursday evening had claimed the wickets of Jonathan Trott and Keith Barker to push Warwickshire to the brink, wrapped up what is only a second win of the season for last year's runners-up by bowling the rookie spinner Sunny Singh just as the ground staff were preparing to power up the hover cover. In the celebrations that followed, the relief was palpable.
"In the context of the season it is a huge win for us and we're absolutely delighted," their young captain, Tom Abell, said. "We asked for the effort and the character to come to the fore and we certainly saw that.
"From the great start we were given by Tres (Marcus Trescothick) and Eddie Byrom on the first morning we performed well in all disciplines throughout the game. As a batting unit we established those partnerships we have been striving for all season and with the ball we were very patient. There was a bit in the wicket for all concerned and when we created chances we took them."
It still might not be enough, of course, to keep Somerset out of Division Two themselves next year. They remain second bottom, 30 points clear of their beaten opponents here but with still work to do if they are to catch Yorkshire or Middlesex and only three matches remaining. In their favour, though, two of them are at home, where Bess and Jack Leach, the most successful spin combination in Division One this year, can expect every bit of assistance possible from the wicket.
"Yes, we still have a lot of work to do," Abell added. "It is a boost to our confidence to get this win and play so well but we are still down there at the foot of the table and we have a massive three games ahead of us. We will be trying to win all three and if we could get two wins, that would be great. It is a very strong division with strong teams but we think we have enough in our dressing room to do it."
It has been the collective failure of the batsmen that has been Somerset's downfall this year, putting them in a predicament few could have foreseen when they went so close to winning the Championship 12 months ago. No one has felt the weight of responsibility more than Abell himself, who had been so out of touch with the bat recently he had no sensible option other than to give up his own place in the side - winning it back, with some irony, only after the controversial move to Warwickshire of Adam Hose created a vacancy.
Abell paid generous compliments to Trescothick, his second-innings centurion, James Hildreth, with whom the veteran opener shared the key partnership of the match to take the game out of Warwickshire's reach, and to the 20-year-old opener Byrom, who played nicely in both innings. Yet his own contributions - a half-century in each innings on a difficult, turning track - were equally significant.
"It has been difficult," he said. "I went through a patch where I didn't know where my next run was coming from and that spell in the Seconds trying to find some form did me the world of good.
"Now I'm starting to find some enjoyment batting again and the confidence in my game that I had lost."
The key to winning here was that every passage of play saw one Somerset player or another produce a performance at a key moment, ensuring that Warwickshire were never on top, even briefly. After the combination of Leach's left-arm spin and Craig Overton's pace had bowled out Somerset for 146 in the first innings, it was the off-spinner Bess and the big-hearted Tim Groenewald who landed the blows second time around.
Once the final exchanges began after a two-hour delay, Overton claimed his fifth victim of the match as Tim Ambrose was leg before and then Groenewald, with new ball in hand, bowled Chris Wright and saw Jeetan Patel brilliant caught by Bess at point to complete a deserved five-wicket haul, his first of the season.
There seems no escape now for Warwickshire, whose relegation may well be confirmed next week, on live television, when the Sky cameras turn up in the hope of seeing Essex, the champions-elect, strut their stuff.
It was a long time after the finish before anyone emerged from the home dressing room, where one can only assume that the atmosphere match the colour of the sky. The bowling coach, Alan Richardson, was ultimately designated to offer words of explanation for a performance that lacked conviction at the moment it was most needed.
"It was highly disappointing," Richardson said. "We had four massive games, starting with one against the team immediately above us, and to not really show up is hugely disappointing."