Somerset 184 and 103 for 1 (Dickson 55*, Fuller 1-23) trail Hampshire 336 (Gubbins 82, Dawson 72, Pretorius 5-64) by 49 runs
Migael Pretorius' bowling and Sean Dickson's batting swung the advantage away from Hampshire in their Rothesay County Championship fixture with Somerset.
South African Pretorius picked up 5 for 64 as Somerset only allowed the hosts a first innings lead of 152, despite Nick Gubbins' 82 and Liam Dawson's 72.
That edge was whittled down to 49 for the loss of just Archie Vaughan as Dickson ended his start-of-the-season drought with a calm unbeaten half-century before the dingy light descended on the Utilita Bowl.
Hampshire began the day with a 10-run lead and the hopes of a large extension of that, which would mean they could win the match without batting again.
But Tom Lammonby's work with the old ball and then Pretorius' with the new stymied them - despite managing to pick up two batting bonus points.
Gubbins and Dawson had ground out a 76-run partnership the previous evening, but opened up a little in the morning - with the former taking a particular liking to Alfie Ogborne.
The stand grew to 125 in a demoralising first half an hour of the day for Somerset - which also saw Dawson dropped by Tom Abell at midwicket - before the visitors began to fight back.
Left-armer Lammonby had only bowled five wicketless overs in the opening two matches of the season, but his two maiden overs on the second evening had been the best on show for his side. He found good movement with the old ball and struck three times before the 80th over.
Gubbins got stuck on the crease and was plumb lbw, Dawson couldn't keep a cut shot down and was well held by Vaughan, and Brett Hampton lasted three balls before he was leg-before to a ball that swung back.
Ben Brown was the constant as three of the last four batters reached double-figures in quick time but couldn't stick around. James Fuller went first and hit 15 in 21 balls, including two stunning cover drives, but departed in the fifth over of the new cherry, as Pretorius nibbled one in to take the edge to second slip.
Toby Albert - who dropped down the order because a back spasm - was lbw while falling over an angled in ball from Pretorius.
And after Kyle Abbott had whacked an 11-ball 20, Pretorius completed his second five-wicket haul for Somerset with a legside catch behind to James Rew.
Ogborne ended the innings when Brad Wheal - after 19 off 16 - had his stumps rearranged, leaving Brown on 30 and still yet to be dismissed on his home ground as club captain.
A lead of 152 would have been below Hampshire's hopes, but still large enough to mount a victory effort. But an increasingly flat pitch and a stout top-order batting performance quelled their hopes of a quick victory, and made the draw the favourite result, especially with rain forecast on the final day.
Vaughan and Dickson's opening partnerships list had read a dismal: 21, 14, 4 and 14 but they roused to 50 with little fuss. Vaughan departed after looping a catch up for deep square leg for the second match in a row, but Dickson battened down the hatches and refused to give away his wicket.
The former Kent batter had a top score of 11 in five innings this season but never looked in danger - except for a wild unprovoked swing which barely missed his leg stump - to reach his fourth fifty for Somerset in 108 balls.
Bad light brought tea forward by 10 minutes, and when they belatedly returned, only four overs of spin were possible before things turned terminally dark.
