|Leicestershire 173-6 beat Derbyshire 171-3|
Ex-Derbyshire all-rounder Wayne White condemned his old team mates to defeat as holders Leicestershire produced only their second FL t20 win of 2012.
White hit the final ball of the game to the fine leg boundary to earn victory.
Derbyshire's 171-3 was built around an unbeaten 55 from Wes Durston and the visitors looked out of it when they needed 37 from the last three overs.
But, after 23 came from the penultimate over from Alex Hughes, White and Robert Taylor saw their side home on 173-6.
Derbyshire hit their biggest total in this season's competition, but they ended the night swapping places with Leicestershire, who climb off the foot of the north group table.