An inspired spell of pace bowling by Anthony Ireland left Derbyshire's quarter-final hopes hanging by a thread as Leicestershire thrashed them by 79 runs in the Friends Life t20 North Group game at Derby.
Ireland took 4-11 in his four overs, which contained 14 dot balls, as Derbyshire were routed for 79 - their lowest ever Twenty20 total - in 14.1 overs chasing Leicestershire's total of 151-6.
Derbyshire never recovered from Ireland's burst which reduced them to 22-4 and Josh Cobb took 3-19 and Shakib Al Hasan 2-7 as the innings folded in abject fashion.
Leicestershire came into the game with no chance of reaching the quarter-finals but they set a decent target after Cobb won the toss on a glorious summer's evening.
At one stage, the Foxes looked like making a more challenging total after Cobb and Greg Smith, with 42 off 30 balls, established a solid platform with an opening stand of 48 in seven overs.
Cobb drove Tim Groenewald for six before he pulled Peter Burgoyne's off-spin to long-on - and although the Foxes reached the half-way point on 82-1, they were unable to break free against some disciplined bowling and hit only four fours in the last 10 overs.
Smith cut Alex Hughes to backward point, Shakib fell to an ugly swipe at Dan Redfern for only three and when Ned Eckersley drilled Hughes to long off, Leicestershire were 125-4 in the 17th over.
Niall O'Brien's attempts to improvise failed to come off and despite some fumbles in the field, Derbyshire had restricted the visitors to 41 from the last six overs.
In reply, Wes Durston pulled Robbie Williams over deep midwicket for six in an opening over which cost 14 but that was as good as it got for Derbyshire as Ireland destroyed the top order with four wickets for three runs in 11 balls.
Chesney Hughes lobbed a pull to mid-on and Durston was bowled for eight before Derbyshire skipper Wayne Madsen was defeated by some late movement and caught behind.
When Redfern edged a pull to the wicketkeeper, Derbyshire had lost four wickets for eight runs in 17 balls and when Richard Johnson was bowled by Rob Taylor, they were 35-5.
Derbyshire's hopes of pulling the game out of the fire now rested on Shivnarine Chandepaul but after reverse-sweeping Cobb for the first boundary in 28 balls, he drove the next to long-off, where Ireland took a good running catch.
The last three wickets quickly followed and Derbyshire now need to beat Durham convincingly on Sunday to have even an outside chance of advancing as the best third placed team.