Derbyshire 181 for 2 (Godleman 92, Reece 51) beat Worcestershire 161 for 7 (Guptill 45, Critchley 4 for 36)
Worcestershire missed the chance to close the gap on Vitality Blast North Group leaders Lancashire when they lost by 20 runs away at Derbyshire Falcons, who moved into the top four.
Billy Godleman made 92 from 65 balls, his highest T20 score, and Luis Reece 51 as the Falcons posted an imposing 181 for 2.
Former Derbyshire batsman Martin Guptill hit 45 from 40 balls but legspinner Matt Critchley celebrated his 23rd birthday by taking 4 for 36 as the Rapids subsided to 161 for 7.
It looked promising for the visitors when Dillon Pennington opened with a maiden but that was the calm before the storm as Godleman reeled off a salvo of boundaries in the next two overs.
Wayne Parnell’s first ball was launched over the long off boundary and Pennington was driven for three consecutive fours before Reece dispatched Parnell several rows back into the stand at the City End.
The Falcons took 57 from the powerplay and the runs continued to flow as the openers rotated the strike with the Rapids rarely threatening to take a wicket.
Godleman reached 50 from 29 balls and after his side had reached the halfway point on 87 without loss, the pair scored freely without taking any undue risks.
Reece pulled Joe Leach for his sixth four to bring up his 50 from 38 balls and the Rapids had to wait until the 16th over for the breakthrough which came when Reece drilled Daryl Mitchell to cover.
They had slowed the scoring rate, though Goldeman passed his previous highest T20 score of 77 by lifting Ed Barnard over wide mid-wicket for his ninth four.
Wayne Madsen drove Parnell for six but after Godleman failed to clear the man on the deep cover boundary, Leus du Plooy hit the last two balls from Pat Brown for four.
Although the Falcons looked on course for 200, the Rapids faced a tough chase which became harder when the dangerous Riki Wessels failed to respond to Guptill’s call and was run out in the second over.
Ferguson powered Boyd Rankin high over midwicket for six and pulled the next ball for four before Guptill drove Reece for six over long-on to leave the Rapids needing 100 from the last 10.
But the introduction of Critchley proved decisive as Ferguson drove him to long-on, Guptill was bowled trying to cut, and Parnell, after driving him for six, failed to clear long-off when he tried to repeat the shot.
Ben Cox and Barnard both drove him for big sixes but the night belonged to Critchley and the Falcons, as Worcestershire came up well short.
The result means that Derbyshire jump from eighth to fourth in the group, and with just three points separating second-placed Nottinghamshire and Northamptonshire in eighth, things could hardly be closer.