Somerset 437 (Trescothick 218, Allenby 63, Myburgh 54, Tahir 7-112) and 100 for 0 (Myburgh 58*) beat Nottinghamshire 401 (Mullaney 165, Libby 90) and 135 (Libby 44, Allenby 3-23, Gregory 3-27) by 10 wickets

Somerset supporters who criticised Chris Rogers in the wake of last week's agonising last-over defeat against leaders Middlesex might look at the Division One table as it stands and be tempted to reiterate their point.

The Somerset captain spoke of "breathing space" at the bottom of the table after watching his side take advantage of Nottinghamshire's dismal last-day performance to run away with a comprehensive victory. Yet in moving ahead of Yorkshire, Somerset are in a position to be considered as rather more than strugglers.

The gap between themselves and Middlesex is just 22 points, with six matches to play. Clearly, then, what happened last week at Taunton, when Middlesex chased down a target set by Rogers with two balls to spare, could yet be hugely significant.

By contrast, Nottinghamshire are unequivocally in trouble. Without a win since the opening match of the season, they have only five matches remaining, including trips to Scarborough and Chester-le-Street. Their two home fixtures are against Hampshire and Middlesex and they conclude by meeting Somerset again at Taunton.

Moreover, they fell apart here in the manner of a team with considerable momentum pulling them in the wrong direction. After resuming on 58 for 2 overnight, they subsided from 74 for 2 to 99 for 7 in the space of 19 overs before lunch before being dismissed for 135, with Brett Hutton unable to bat because of an injured hand.

The deliveries that accounted for Brendan Taylor and top-scorer Jake Libby kept a touch low and Chris Read, himself only recently back from a hand injury, was out in bizarre fashion, pulling a ball from Lewis Gregory over the rope at midwicket but knocking off the bails with the toe of his bat as he swivelled round in his follow-through.

It did not add up to anything like mitigation, however. When Samit Patel casually flicked a ball from Gregory straight into the hands of James Hildreth on the square-leg boundary, he threw back his head partly in disbelief, partly in the grim realisation that the spectre of relegation is looming uncomfortably large.

It left Somerset needing just 100 to win, which they were able to knock off in just 16.5 of the 53 overs at their disposal. Johann Myburgh, who had riotously smashed 22 in one over of Imran Tahir's leg spin, hit the winning runs. At the other end stood his opening partner, 40-year-old Marcus Trescothick, first-innings double centurion, who had been on the field, give or take the odd comfort break, for every baking minute of the match.

It meant that Nottinghamshire, having been 196 for 0 on day one and 295 for 2 after 24 overs on day two, had ultimately had their faces rubbed in the dirt. Speaking afterwards, director of cricket Mick Newell was not inclined to pull punches.

"We've got ourselves into big trouble now," he said. "We have to face the fact. We're seventh, which is where we deserve to be and we have to make sure we don't drop any lower.

"To get bowled out for 135 on that pitch is poor but the fact is that 401 should have been 501 in the first innings.

"We are getting out of positions of strength too easily and under pressure we have not shown enough fight. Those are the two things you need to do if you want to be a better team and the fact is that we are not playing very well."

Rogers took the opportunity to revisit the debate over the Middlesex defeat, in which he came under fire for making what some perceived as a risky declaration. He was willing to accept the criticisms, but believes the experience of a narrow defeat actually did his young team more good than harm.

"I read somewhere that I didn't have regrets about declaring," he said. "Of course I had regrets - we lost the game.

"It left us feeling low but this group is going to get better by being in tough positions. You don't learn from playing out boring draws. You learn from being under pressure.

"We have a fantastic group of young players at Somerset for whom the sky's the limit and we have to challenge them.

"They responded so well to that loss and to see that response here, in one of the most incredible games I've played in, where losing the toss felt like a hammer blow, is so promising.

"Of course, we could have been in a tough situation if we had not won so this is a huge result, giving us a bit of breathing space and allowing us maybe to attack the teams ahead of us."

Newell said that Hutton has a broken bone in his right hand as a result of an incident in the field on day three and will be missing for four weeks, which is a further blow to Nottinghamshire's survival chances.

The emergence of Hutton, Jake Ball and Luke Wood as a trio of vibrant young bowlers helped turn Nottingham's season around from a similar low point last year but although Wood will be back from injury by the time they next play a Championship match, there are few other signs of an imminent fillip. The loss of James Taylor and, through England's demands, of Alex Hales, is being keenly felt.

"We've got three and a half weeks now of white-ball cricket, in which we are doing well, and we just have to hope that when we come back against Hampshire on August 13 some of that form transfers to the four-day game," Newell said.

"We have to find a way to get 60-70 points from the last five matches and at least one win will be essential."