Shropshire, Norfolk, Cambridgeshire, Hertfordshire and Cornwall all progressed to the quarter-finals of the MCCA Trophy following victories in the latest round of matches.
The five counties will join Wales MC in the quarter-finals, leaving just two spots up for grabs going into the final round of matches.
Norfolk progressed following a nail-biting 12-run victory over rivals Suffolk at Bury St. Edmunds.
A fifth-wicket stand of 73 between Harry Bush, who top-scored with 54, and Stephen Gray proved key as Norfolk posted 247 for eight from 50 overs.
Nick Browne, who this week received a call-up to Essex’s squad for the LV= County Championship match at Worcestershire, made a fluent 59 at the top of the order for Suffolk in reply.
However, Paul Bradshaw returned 5-66 to seal Norfolk’s place in the last eight, the seamer striking with successive balls after a ninth-wicket partnership of 60 between Tom Rash and James Poulson had given Suffolk hope.
In the same group, Shropshire progressed with a 100% record following a four-wicket victory over Wiltshire at Oswestry.
Wiltshire were dismissed for 245 in just 34.3 overs, Neil Clark finishing unbeaten on 126 from just 82 deliveries.
Shropshire chased down the target in 40 overs thanks to significant contributions from Richard Oliver, Ed Foster and Anthony Parker.
Cambridgeshire also progressed to the quarter-finals with a 26-run victory against Herefordshire at Stowe Lane.
In a high-scoring encounter, Cambridgeshire posted 326 for seven from 50 overs, former Northamptonshire batsman Ben Howgego top scoring with 97.
Herefordshire looked on course for victory when they reached 228 without loss, Benjamin Stebbings and Liam Gwynne both making centuries.
However, a spectacular collapse followed as Lewis Bruce returned 6-90 to help dismiss the hosts for 300.
Hertfordshire progressed with a three-wicket victory over Bedfordshire and Cornwall enjoyed two victories in two days to book their place in the quarter-finals.
A 16-run victory over Oxfordshire on Sunday was followed by a 56-run triumph over Bedfordshire 24 hours later.
Elsewhere, Berkshire beat Buckinghamshire by eight wickets, Staffordshire defeated Dorset by 21 runs and Northumberland triumphed over neighbours Cumberland by 163 runs.