Somerset 143 for 6 tied with Middlesex 143 for 7
Somerset have secured a place in the quarter-finals of the Friends Life t20 even after Middlesex, bottom of the South Division, snatched a tie in a dramatic finish at Southgate.
Middlesex appeared to be heading for their 12th defeat in 14 games when they began the final over needing 18 off the bowling of Kieron Pollard to overhaul a target of 144 to win.
But Ryan McLaren, who had earlier taken three for 37, struck sixes off successive balls to take them within four of victory. He holed out on the midwicket boundary next ball, but Tom Smith scrambled a two and a single off the last two deliveries to bring the scores level.
Somerset had Craig Kieswetter back from international duty to open the batting alongside Marcus Trescothick, but neither of them got very far on a sluggish pitch.
Trescothick only made eight before he pulled McLaren to deep mid-wicket and was caught by a leaping Smith, while Kieswetter reached 17 off 18 balls when he was caught at wide mid-on off Tim Murtagh.
It was left to Pete Trego and James Hildreth to give Somerset some momentum with a third-wicket stand of 47 in nine overs, but neither of them could really cut loose against some tight bowling from Smith and Neil Dexter. Smith got his reward when Trego top-edged to backward point after making 36 off 33 balls and two overs later McLaren yorked Hildreth, who had struggled to 31.
There were some late fireworks from Pollard who struck 33 off 18 balls, including two huge sixes, but there were only nine fours and three sixes in the entire innings. A total of 143 for 6 still looked too good for Middlesex, who lost wickets at regular intervals.
Louis Gregory was the main protagonist for Somerset, taking three for 26 including joint top-scorer Dexter, who matched Scott Newman's contribution of 33. But then came McLaren's spectacular finale, the South African allrounder making 25 off 17 deliveries.