Wes Durston hit 83 as Derbyshire clinched their second straight Friends Life t20 victory, beating Leicestershire by 24 runs at Grace Road.
Chasing a target of 174, Leicestershire lost eight wickets for 52 runs to collapse from 97-2 to 149 all out in 18.2 overs.
Josh Cobb's 47 off 26 balls - with six fours and a six - gave Leicestershire a flying start to the chase as he dominated an opening stand of 54 in six overs with Niall O'Brien.
Even when O'Brien was bowled trying to sweep Dan Redfern, Leicestershire still looked on course at 87-2.
But a fine catch at cover by David Wainwright to dismiss Shakib Al Hasan off the bowling of Albie Morkel proved the turning point.
Although Australian Joe Burns made 36 off 25 balls hitting three fours and two sixes, he found little support from the rest of the side with wickets falling in clusters.
In addition to his airborne catch, left-arm spinner Wainwright claimed 3-24 runs in his four overs and Redfern and Morkel picked up two each.
Put into bat, Derbyshire posted 173-3 with Durston leading the way with 83 off 62 balls. He shared an opening stand of 48 with Chesney Hughes and then a second-wicket partnership of 94 with Shivnarine Chanderpaul.
Durston struck five fours and three sixes before finally being dismissed in the 20th over with a leg-stump yorker from Robbie Williams.
Hughes (34) and Chanderpaul (38) kept Derbyshire's innings ticking over but Leicestershire restricted them to 40 runs off the last five overs and would have fancied their chances of chasing down 174 to win.
Instead they slumped to a second defeat in 24 hours and now have a lot to do to qualify for the knockout stages of a competition they have won three times.