Derbyshire captain Wayne Madsen struck his second successive Royal London One-Day Cup century to lead his side to a seven-wicket victory against Leicestershire at Grace Road.
Madsen, who scored 138 in the win over Hampshire on Saturday, hit an unbeaten 105 as Derbyshire successfully chased down their target of 249 with 4.5 overs to spare. Shivnarine Chanderpaul made an unbeaten 52 and shared in a match-winning fourth-wicket partnership of 128.
The Foxes had been restricted to 248-8 mainly by Mark Footitt, the in-form seamer claiming 5-59. Matthew Boyce was one of his wickets, removed for a top score of 64.
The left-armer did not dismiss Josh Cobb but did force him from the field, the Leicestershire captain having to retire hurt with his score on 20 after taking a nasty blow to his right hand.
In other Group A fixtures, another unbeaten century - this one from Mark Pettini - steered Essex to a convincing eight-wicket triumph over Worcestershire at New Road.
The Eagles made the perfect start to the new 50-over tournament as they eased past the home side's score of 238-7 at New Road with 46 balls remaining.
Pettini finished up on 102 not out from 112 balls, the opener having shared in a second-wicket stand worth 109 with Ravi Bopara (59). Jesse Ryder rushed Essex over the line, hitting five sixes and six fours to make 68 from just 51 deliveries.
Graham Napier had earlier claimed 4-59 to restrict Worcestershire's progress, though unbeaten knocks of 45 and 44 from Jack Leach and Shaaiq Choudhry respectively helped lift the hosts after they'd slumped to 145-7.
Adam Rossington registered his highest score in limited overs cricket to help Northamptonshire to a four-wicket victory over Gloucestershire at Cheltenham.
Rossington, on loan from Middlesex, made 82 from 91 balls, hitting 12 fours in the process, as the visitors overcame Gloucestershire's total of 240-9 with almost eight overs to spare.
Skipper Michael Klinger had held the Gloucestershire innings together with 98 from 131 deliveries, but David Willey claimed 4-33 to peg back the hosts. He then hit an unbeaten 26 to see Northamptonshire home to a second win in as many outings in the competition this season.
Lancashire, however, are still yet to win in the new 50-over domestic tournament after suffering at the hands of Hampshire batsman Glen Maxwell at Old Trafford.
The Australian smashed a limited overs career-best 146, his first Hampshire century, which carried his side to a mammoth 360-9, a target their opponents never looked like hunting down.
Lightning captain Paul Horton top-scored with 57 off 50 balls but the Red Rose county were only able to muster 212 all out inside 38 overs, meaning a 148-run win for the visitors.