Durham booked their place in the Royal London Cup semi-finals with a nine-wicket win over Hampshire at Emirates Riverside.
Chris Rushworth claimed 4-37 as Hampshire eventually recovered from 65-6 with a career-best 79 by Felix Organ to post 225-9.
Graham Clark then struck a third century of the season with an unbeaten 141 as Durham cantered towards the semi-finals in reaching 228-1 in 40.4 overs, captain Scott Borthwick finishing 71 not out. Durham vs Hampshire scorecard
Surrey booked their place in the quarter-finals with an eight-wicket victory over Derbyshire at the Incora County Ground, where Ryan Patel made a century. Derbyshire vs Surrey scorecard
Patel led the way with an unbeaten 111 from 116 balls and Tim David added a rapid 52 off 38 balls as Surrey chased down a modest target with 13 overs to spare, finishing 219-2.
Derbyshire - who saw all-rounder Fynn Hudson-Prentice ruled out following a positive Covid-19 test - could only make 215 all out, with Mattie McKiernan top-scoring on 38 as Conor McKerr and Daniel Moriarty each took three wickets.
Chris Dent hit an unbeaten 112 as Gloucestershire cruised to an eight-wicket win over Kent with 74 balls to spare at Beckenham, which saw them qualify following Essex's dramatic tie against Lancashire at Old Trafford.
Graeme van Buuren added an aggressive unbeaten 51 as Gloucestershire, who had to deal with a Covid-19 outbreak in the squad ahead of Thursday's match, closed on 219-2. Kent vs Gloucs scorecard
Ollie Robinson made his highest List A score of 75, but Kent failed to build on a solid opening partnership and were restricted to 218-9 as Van Buuren capped a good all-round performance with 3-34.
Former England captain Sir Alistair Cook struck a century to help Essex progress and end Lancashire's hopes at Emirates Old Trafford. Lancashire vs Essex scorecard
Essex, who were eight wickets down, had required 22 off the last over to win before Simon Harmer hit three successive sixes off Steven Croft with a scrambled two from the last ball leaving the scores level. Cook made 110 from 128 balls, including 11 boundaries.
The result meant the visitors finish second in Group A behind leaders Durham, while Lancashire, who had to win to qualify, dropped to fourth after posting 250-6.
Yorkshire secured their place in the knockout stages after battling to a four-run win over Glamorgan at Sophia Gardens. Glamorgan vs Yorkshire scorecard
The Vikings rallied from 132-7 to post 230 all out, with Jonny Tattersall making 53.
Group B leaders Glamorgan - who have secured a home semi-final despite the defeat - looked to be on course following an opening stand of 121 between Hamish Rutherford (58) and Nick Selman (92), but George Hill claimed three wickets in six balls as the hosts then struggled on to reach 226-8.
Captain Tom Haines and Ben Brown both scored their maiden List A centuries as Sussex ended their campaign by beating Middlesex by three runs at Hove. Sussex vs Middlesex scorecard
Haines made 123 and Brown 105 as they shared a stand of 219 for the second wicket from a total of 333-4.
Middlesex - who needed to win to have any chance of qualifying for the knockout stage - fell just short, despite 94 for opener Max Holden and a rapid 51 from left-hander Jack Davies.
Leicestershire missed out on a knockout spot despite a Louis Kimber-inspired four-run DLS victory over Northamptonshire at Wantage Road.
The Foxes needed to win and hope for two of Surrey, Somerset and Yorkshire to lose but in spite of holding up their end of the bargain they fell a point shy in Group B. Northants vs Leics scorecard
Kimber struck 63, his second List A fifty, with Rishi Patel, Arron Lilley and Rehan Ahmed's 40-odds helping the Foxes to 271 all out.
Rain meant the Steelbacks needed 266 from 48 overs, but Rob Keogh's 52 was not enough as they fell agonisingly short - with Will Davis, Gavin Griffiths and Ben Mike all taking two wickets apiece.
Warwickshire beat Somerset by three wickets in a thriller at Edgbaston to spoil the west country side's hopes of qualification for the knockout stage. Warks vs Somerset scorecard
The home side went into action with qualification already beyond them but their youngsters delivered an impressive victory driven by a powerhouse all-round display from Matt Lamb.
Lamb's List A best bowling 4-35 limited Somerset to 287-8 after a third-wicket stand of 118 between Lewis Goldsworthy (79) and James Hildreth (72) left them apparently heading for 300-plus.
The 25-year-old then scored 92 as the Bears reached 289-7 with six balls to spare - at 108 for four, they were on the back foot but Somerset's qualification bid was then unpicked by stands of 77 between Lamb and Dan Mousley and 88 between Lamb and Jacob Bethell.