Somerset 333 for 5 (Umeed 172*, Dickson 67, Reece 3-62) beat Derbyshire 261(Dal 110, Davey 3-18, Leonard 3-40) by 72 runs
The pair plundered 111 off the last 10 overs to take Somerset to 333 for 5 with Umeed registering the highest one-day score against Derbyshire at Derby.
It had earlier looked promising for Derbyshire when George Thomas aimed a firm footed drive at the third ball of the innings from Sam Conners and was well caught low to his right at first slip by Harry Came.
Both Conners and the impressive 16-year-old Harry Moore got some early movement with the latter unlucky to have Lewis Goldsworthy dropped on six by Came in his second over.
Umeed began to assert himself, twice driving Conners down the ground for boundaries and pulling Dal to the ropes before swatting Luis Reece back over his head for six.
Goldsworthy hoisted off-spinner Alex Thomson over the wide long on boundary and the stand had reached 90 from 110 balls when he drove back a return catch to Reece.
James Rew showed his intent with consecutive fours off Reece and a reverse sweep to the ropes against Thomson so Derbyshire were relieved to see the back of the 19-year-old.
Rew had scored a run-a-ball 31 when he launched a big drive at Conners and got an inside edge which Brooke Guest did well to hold diving to his right.
But Umeed was playing with the assurance of a man who had already scored two hundreds in the tournament and after driving Conners over long off for six, he reached three figures off 106 balls.
After passing his previous List A best of 119, he pulled Moore for a four and two sixes with 23 coming off the 43rd over.
Although Dickson’s 50 contained only three fours, it had come off 43 balls which showed how good his placement had been on both sides of the wicket with Derbyshire unable to prevent the pair accelerating towards a formidable total.
Umeed brought up his 150 with a straight six off Mark Watt and Dickson drove Conners for six before he was lbw to Reece.
Reece was pulled by Umeed for another six but the all-rounder at least restricted Somerset to five off the last over although the damage had already been done.
Faced with pulling off their highest ever one-day run chase, the home side stumbled from the outset, losing Reece in the first over, given out caught behind by Sue Redfern, the first female umpire to stand in a Derbyshire match.
Tom Wood miscued a pull at Ned Leonard, Came drove Davey to extra cover and Matt Lamb skied a pull in the fourth over.
Guest was bowled by one that kept low and after pulling Goldsworthy for six, Haider Ali swept the left-arm spinner to deep midwicket.
Somerset looked set to wrap up victory early but Dal had other ideas, reaching his hundred from 103 balls,and sharing stands of 81 from 79 balls with Thomson (42) and 88 for the last wicket with Conners to at least restore some Derbyshire pride.
Source: ESPN Crickinfo