Match scores (Derby)
Derbyshire beat Warwickshire by four wickets
Warwickshire inns: 292-7 (50/50 overs. Hain 109, Bell 93, Ambrose 32; Thakor 3-48)
Derbyshire inns: 296-6 (49.4/50 overs. Slater 82, Godleman 46 no; Clarke 2-55, Patel 2-57)
Match report
Defending champions Warwickshire are out of the Royal London One-Day Cup after a four-wicket defeat to Derbyshire.
Sri Lankan all-rounder Jeevan Mendis hit an unbeaten 44 off 23 balls to steer Derbyshire home with two balls to spare and keep their hopes alive of finishing in the top three of the North Group.
The visitors' 292 for seven was built on Sam Hain's highest one-day score of 109 and Ian Bell's 93 but Ben Slater set Derbyshire up with 82 before Mendis carried the hosts to victory.
Warwickshire remain bottom of the table and are unable to qualify for the knockout stages.
The 2016 winners would have expected to go past 300 when Hain and Bell put on 182 after Jonathan Trott had played on to Ben Cotton in the eighth over.
Hain's second 50 came from only 38 balls but when he gave himself room to drive Shiv Thakor through the covers, he lost his middle stump which ended Warwickshire's highest stand for any wicket against Derbyshire in one-day cricket.
Bell's run out four overs later going for a second on a misfield meant Warwickshire had two new batsmen in and the innings stalled against tight bowling backed up by sharp fielding.
Rikki Clarke went cheaply against the club he used to captain and although Tim Ambrose pulled Ben Cotton for two consecutive sixes, he was lbw hitting across the line at Thakor.
When Hardus Viljoen conceded six runs in the final over, Warwickshire had been restricted to 44 from the last seven.
Derbyshire were given a solid start by Slater and Billy Godleman who made 46 before he was sent back and run out in the 18th over as the spinners checked the home side's progress.
Clarke profited when he returned to have Thakor caught at deep mid on for 20 and although Slater pulled Ateeq Javid for six, he was bowled attempting the same shot at Patel two overs later.
When Wayne Madsen was lbw to Keith Barker, Derbyshire needed 120 from the last 15 overs but Daryn Smit pulled Mark Adair for four and six to reduce the target to 84 from 10.
Alex Hughes helped add 62 in nine overs before Mendis took over, clubbing Clarke for six before he sealed victory with a drive down the ground off Barker.