Durham leapfrogged opponents Worcestershire in the Friends Life t20 North Group with a 28-run victory at Chester-le-Street on Sunday.
Paul Collingwood starred with the ball, taking 4-19 to propel his side into third place in the table after the hosts had set a target of 161-6.
After winning the toss and electing to bat under cloudless skies Durham made a shaky start, losing Phil Mustard to the second ball for a duck when he was bowled by Jack Shantry.
But his dismissal brought Blackwell to the crease, who went on to underpin the hosts' innings with 77 from 59 balls, including four sixes and six fours.
Opener Gordan Muchall departed in the fifth over having made just 10 when he lofted Saeed Amjal straight to deep midwicket
But Blackwell and Collingwood added 71 for the third wicket until the former England T20 captain, who has made just 30 runs in his last six Twenty20 innings, fell on 29.
With Durham on just 106-3 after 15 overs, Dale Benkenstein joined Blackwell to take 30 runs off the next 10 balls, before Blackwell was caught and bowled by Bangladesh all-rounder Shakib Al Hasan Al Hasan.
In the end Durham's score looked a little modest given the conditions but Collingwood more than made up for his recent poor batting form to frustrate Worcestershire's reply.
Collingwood struck twice in two balls in his first over, first having Moeen Ali stumped for 29 then holding a return catch offered by Al Hasan.
Opener Ali top scored in a Worcestershire batting attack that offered little in substance and Amjal became the last man to fall with five balls remaining and the visitors on 133.