Graeme White took four wickets as the Northamptonshire Steelbacks saw off fellow Midlands, Wales & West Group side Gloucestershire Gladiators to claim their first home win in the Friends Life t20 in almost three years.
After the weather saw the match reduced to 12 overs a side, the Steelbacks batted well in making 124 for four with Scotland captain Coetzer top-scoring by smashing 39 off 25 balls.
The Gladiators never looked like reaching their target as they collapsed to 83 for nine with Nottinghamshire loanee Graeme White taking a brilliant 4-14 from three overs with Muhammad Azhar Ullah claiming 2-23.
This was the hosts' first victory in this competition at Wantage Road since they defeated Lancashire in July 2010 and it gets this year's campaign off to a flyer.
Several rain delays meant proceedings eventually began at 8:10pm after the Gladiators won the toss and put the Steelbacks in to bat.
Dan Christian then dismissed Richard Levi in the second over when he chased the Australian's wide delivery and was taken by Gloucestershire wicketkeeper Gareth Roderick.
Coetzer departed when he chipped Benny Howell to Gladiators' captain Michael Klinger at extra-cover before the same bowler castled Cameron White after he had clubbed 28 off 20 balls.
The Steelbacks' captain Alex Wakely bludgeoned 36 off only 19 deliveries before smashing David Payne to Ian Cockbain at long-off with the last ball of the innings.
Chasing 125, Gloucestershire lost Hamish Marshall with just the second ball when he launched David Willey to Cameron White at midwicket before Chris Dent dragged Azhar on to his stumps.
The visitors then lost two wickets in consecutive balls in the eighth over, bowled by White, when Christian picked out Willey at long on.
Klinger was taken at long-off by Matthew Spriegel after plundering 27 as the game slipped away from the Gladiators.
Five wickets then tumbled for just three runs as Howell was superbly run out by Willey at long-on before White caught and bowled Gidman with the next ball.
White then bowled James Fuller before Azhar repeated the dose to Cockbain and Roderick in the penultimate over to compound the visitors' misery.