Northamptonshire 135 for 3 beat Derbyshire 133 for 5 by seven wickets
South African allrounder Johan Botha showed his international pedigree at Derby to give Northamptonshire a rare Friends Life t20 victory and end Derbyshire's faint hopes of reaching the last eight.
Botha conceded only 14 runs from his four overs of off-spin and than scored an unbeaten 54 from 48 balls as the Steelbacks cruised past the Falcons' 133 for 5 to seal a seven-wicket win - only their second in the North Group.
Derbyshire needed an unbroken stand of 82 in eight overs from Garry Park (50) and Ross Whiteley, who hit 39 from 26 balls, to give them a respectable total. However, Botha and Rob White, who weighed in with 51, ended the home side's chances of victory.
The Falcons had been struggling to reach three figures after thoughtful tight bowling restricted them to 66 for 5 after 15 overs. Martin Guptill drove the first ball to the boundary but that proved deceptive as the Steelbacks bowled straight and full to frustrate the batsmen.
After Wes Durston was caught behind and Greg Smith was leg before wicket padding up, Wayne Madsen was run out backing up before Guptill failed to clear long-off. t the halfway mark, Derbyshire were 46 for 4 and when Chesney Hughes was caught behind in the 12th over, Northamptonshire were firmly in control.
Derbyshire did not hit a boundary for 12 overs until Park drove Rob Keogh for six but that broke the shackles as Whiteley swept the spinner high over the midwicket boundary. Whiteley drove Jack Brooks for another six as 67 came off the last five overs, although Andrew Hall strangely ignored strike bowler David Lucas - who had conceded only eight runs from two overs.
Northamptonshire were still only chasing a modest total and although they quickly lost David Murphy to a brilliant leaping catch at cover by Guptill, White and Botha steadily chipped away at the target.
It might have been different if White had not been dropped by Hughes at slip before he had scored but Derbyshire were never able to exert any pressure on the second wicket pair - who added 109 to take the Steelbacks to the brink of victory.
White drove and pulled Jon Clare for three consecutive fours to reach his half-century from 43 balls and Botha reached the milestone in style by pulling Whiteley over the midwicket boundary. White was caught behind cutting at Mark Turner, who then bowled Alex Wakeley. However, the fast bowler then sent down a wide to give the visitors victory with 10 balls to spare.