North Division leaders Durham booked their place in the quarter-finals after beating Derbyshire by seven wickets under the Duckworth-Lewis method.

Derbyshire rallied to post 118-6 after the match was reduced to 18 overs.

Chasing a revised 121 after low sun again caused problems at Derby and an 85-minute delay, Durham were 31-3.

But Dale Benkenstein and Albie Morkel shared an unbroken stand of 93, Morkel ending the match with 16 balls to spare with a six to finish on 54.

Rikki Clarke bolstered Derbyshire by taking 17 from teenage leg-spinner Scott Borthwick's only over, which included a six over long-on and two powerfully hit fours.

Dan Birch drove the first three bowls from Ben Harmison for four in another expensive over, which cost 15.

Clarke pulled Steve Harmison for another six before he sliced to deep cover.

Durham's chase began badly when former Derbyshire batsman Michael Di Venuto chipped the third ball to mid off and Phil Mustard cut to point where Smith held a juggling catch.

Benkenstein and Morkel put them back on track and 58 were needed from the last nine overs.

Morkel accelerated in the 15th over when he drove Jon Clare over the long-on boundary and deposited the next ball to long-off for another four.

That helped bring the requirement down to just seven from the last three overs and the Durham duo ensured that there was no close finish.