Worcestershire Rapids and Durham Jets became the first sides to qualify for the T20 Blast quarter-finals in a rain-affected round of fixtures.
The Rapids lost in a tight game at Leicestershire, but defeat for rivals Birmingham Bears sent them through.
Durham beat Northants by 12 runs which took them top of the north group.
Somerset made it six straight wins by beating Surrey to move to the brink of qualification, while the games at Sussex and Essex were washed out.
Another point in their remaining two matches will send 2005 champions Somerset into the last eight.
The quarter-finals take place between 23 and 26 August.
Elsewhere holders Notts Outlaws piled up 212-5 thanks to Tom Moores 80 not out to beat Yorkshire by 63 runs and keep their hopes of going through alive.
Lancashire’s 37-run victory over the Birmingham Bears kept them in a strong position to make the quarters, while Glamorgan are also well placed to reach the knockout stages after a thumping victory over Hampshire.
Can Worcestershire finally break hoodoo?
Worcestershire, along with Derbyshire, are the only two counties who have failed to reach Finals Day in the 15-year history of England’s T20 competition.
But this season they have picked up a number of impressive victories, led by match-winning performances from their overseas stars and some superb bowling spells by the competition’s leading wicket-taker Paddy Brown.
The 19-year-old seamer could not add to his 22 wickets at Grace Road, conceding 45 runs off his four overs, but Leicestershire’s 155-9 looked below par.
It proved to be enough however as the Rapids fell short on 150-6, despite Callum Ferguson’s 69.
Securing a home quarter-final by finishing in the top two is now next on the agenda for Worcestershire with one victory from their final two games likely to do the job.
The other side in prime position for a home match in the knockout stage are Durham.
The Jets, runners up in 2016, have now won nine of their 12 games as they seek a first T20 title.
Several batsman contributed as they made 174-7 at bottom side Northants, and Chris Rushworth then took three wickets to restrict the Steelbacks to 162-9.
More washouts in the south group
Despite the country baking under sunny skies for weeks, Kent Spitfires and Sussex Sharks have now suffered an incredible four washouts in their 11 games.
Kent still sit fourth in the south group and are in a good position to qualify, while Sussex are two points behind in sixth.
Heavy rain throughout Friday at Hove left surrounding roads under water and the outfield saturated, leaving the umpires with little choice but to call the game off an hour before the scheduled 19:00 BST start.
It was a similar story at Chelmsford between Essex Eagles and Gloucestershire where things were abandoned without a ball bowled.
Essex are already out – Gloucestershire are in second place, two points behind Somerset.
The leaders pulled off an impressive four-wicket victory over Surrey at Taunton thanks to fine half-centuries by Peter Trego (70) and Corey Anderson (53).
The big-hitting pair put on 104 to rescue their side from 55-4, as Somerset reached a target of 177 with five balls to spare.