Surrey made heavy weather of disposing of Essex but eventually prevailed by three wickets, Graham Thorpe giving the England selectors a nudge with 79 not out as the First Division leaders chased an average target of 221.
Mark Ramprakash (38) shared a 72-run third-wicket stand with his former international team-mate and when he had departed Adam Holliaoke (26) and Rikki Clarke (21) eased Surrey closer to their objective. Thorpe, who struck eight fours in his 97-ball knock, saw his side home with 2.1 overs to spare.
Azhar Mahmood had earlier destroyed the Essex batting with six for 37 in his nine overs as only Darren Robinson (78) and Paul Grayson (37) got to grips with the bowling.
Craig Spearman blasted Gloucestershire to a 78-run win over Warwickshire to lift them into third place. The New Zealander hit 153 off just 123 balls as, with Phil Weston's 61, the Gladiators piled up 307 for 8 off their 45 overs. The visitors were always up against it, although Nick Knight (70) and Ian Bell (50) looked like giving their side a chance with a third-wicket stand of 88. Jim Troughton chipped in with 53 but Alex Gidman's introduction into the attack brought him figures of 3 for 26 to help bowl out the Bears for 229.
Glamorgan maintained the pressure on leaders Surrey with a 31-run win over Worcestershire Royals after Alex Wharf's 4 for 24 helped dismiss the visitors for 184. Adrian Dale (60), David Hemp (59) and Mike Powell (46) had earlier contributed to Glamorgan's 215 for 9 off 39 overs.
Yorkshire slipped to their fourth defeat in five National League matches after failing to reach a target of 209 against Kent. Michael Lumb (77) and Richard Blakey (41) were the top scorers for the visitors but Ben Trott's 3 for 19 and two wickets for the Australian all-rounder Andrew Symonds helped dismiss Yorkshire for 186. Kent's total was a real team effort with Greg Blewett top-scoring with 46, with other significant scores coming from Matthew Walker (31), Peter Trego (23no) and Robert Key (22). Ryan Sidebottom's 3 for 39 was ultimately in vain.
The Second Division leaders Northamptonshire put struggling Somerset to the sword with a seven-wicket victory at Bath - their fifth in six matches. The home side were soon in trouble at 35 for 5 as Mike Cawdron ran through them with 4 for 31. Keith Dutch made 50 from 55 balls and 33 from Keith Parsons helped push the total up to 143. However, that was hardly likely to challenge the leaders and when the target was reduced to 131 because of rain it was made all the more easier, as captain Mike Hussey showed with his 54 before David Sales saw the side home with 33 not out.
An aggressive 43 off 31 balls from Andrew Flintoff saw Lancashire comfortably beat Nottinghamshire, who could only post 100 in 17 rain-affected overs. The home side's target was adjusted to 112 under the Duckworth-Lewis method but that did not concern Flintoff, who, with Carl Hooper (40), shared an unbroken fourth-wicket stand of 88.
Kevin Innes bowled Sussex to victory against Middlesex with 5 for 41 as the home side chased a revised target of 181 after the Sharks has posted 161 for 7 thanks to Murray Goodwin's unbeaten 81 and 41 from Tim Ambrose. Only Andrew Strauss (57) had any real impact as the Crusaders were bowled out in the 34th over.
Hampshire moved into second place after restricting Durham's pursuit of 204 to 196 for 8. Dimitri Mascarenhas removed the top three batsmen and finished with 4 for 44. John Crawley's 102 from 134 balls had been the mainstay of Hampshire's 203 for 5.