Somerset 236: Byrom 56; Patel 7-81, Stirling 2-70
Middlesex 18-3: Malan 9*, Voges 4*; Leach 2-3
Close, day one: Middlesex trail Somerset by 218 runs
Middlesex remain in relegation peril after a remarkable first day of their make-or-break clash at Taunton, the final game of the County Championship season.
Thirteen wickets fell, 11 of those to spinners, on a turning pitch – and by the close of play, Somerset were in the box seat in the battle against the drop.
That had seemed unlikely after Middlesex left-armer Ravi Patel had taken full advantage of a dry wicket and some poor batting to record career-best figures of 7-81, and help skittle the hosts for 236.
But Somerset spinner Jack Leach then struck twice, removing Sam Robson (4) and Stevie Eskinazi (1) to leave the deposed champions reeling at 5-3.
By stumps they had reached 18-3, still 232 runs short of the 250 which would give them the batting bonus points they need to secure their safety.
Middlesex lost the toss and had to field and Somerset were looking steady on 193-4, opener Eddie Byrom (56) making his maiden Championship half-century.
But control of the match veered the other way as the visitors claimed the final six wickets for just 43 runs.
Patel breezed past his previous first-class best of 5-69, including two in two balls, as Somerset appeared to have let a good position slip.
But Craig Overton then produced an excellent opening spell that saw Nick Compton caught behind and Leach used the new ball to good effect, having Eskinazi and Robson caught by Marcus Trescothick at second slip.