Leaders Preston Nomads won by seven wickets against basement side Hastings.
The home side, batting first after losing the toss, made 214 as Harry Finch top-scored with 89, before Nomads eased home with 217-3 in the 46th over.
Roffey reclaimed second place with a seven-wicket win away to Three Bridges.
Bridges, batting first, made 161 as Rohit Jagota claimed 4-42.
Roffey then replied with 165-3 as Mike Norris and Jagota both hit unbeaten 67s.
East Grinstead had a comfortable nine-wicket win over Brighton & Hove.
Brighton won the toss and put on 168-9, before East Grinstead eased home with 173 for the loss of just one wicket. Will Adkin (63) and Alex Carey (68) saw them home, both not out.
Horsham’s Ben Shoare hit an unbeaten 116 and John Burroughs made 66 as they chased down Cuckfield’s 217.
The visitors lost the toss and were asked to bat first and Horsham knocked off their score for the loss of just one wicket, for a nine-wicket victory.
In Division 2, second-placed Billingshurst closed the gap on leaders Middleton with a 62-run win.
Billingshurst lost the toss an were put in to bat and posted 238-7 as Scott Stratton top-scored with 77.
Billingshurst captain Ben Williams then stole the show with the ball as he ripped through the Middleton order.
He finished with figures of 7-56 as Middleton were bowled out for 176.
St James’s beat Lindfield by 54 runs, Crowhurst Park overcame Goring by 84 runs and Worthing beat Findon by 68 runs.
Worthing lost the toss and were put in to bat and made 158, before skittling their visitors for 90 as Mason Crane claimed 6-27.
Chichester Priory Park’s clash with Ifield ended in a draw.
Pagham are the new Division 3 leaders after they beat Glynde & Beddingham by six wickets.
Batting first, Glynde posted 105 runs, before Pagham eased home with 106-4.
Previous leaders Ansty dropped to second after a two-wicket defeat against Crawley Eagles.
Ansty posted 153, which was chased down by Eagles, who scored 156-8.
In the division’s basement battle, third-from-bottom side Rottingdean beat second-bottom Pulborough by 76 runs.
Rottingdean won the toss and scored 226-6, while Pulborough replied with 150 all out.
Haywards Heath and Bognor Regis drew, as did Burgess Hill and Stirlands.
Steyning continued their march to the Division 4 title with a 68-run victory at home to Lewes Priory.
Owain Jones smashed 121 not out as Steyning hit 240-4, before Lewes replied with 172.
Portslade and Wisboorugh Green maintained their race for second as both sides won; Portslade beat Hellingly by 30 runs as Paul Glover hit 128 runs.
Wisborough Green beat Rye by four wickets. The home side bowled Rye out for 205 as Ben Thatcher claimed 5-61 and Rajesh Maru picked up 4-58, before Wisborough came home with 209-6.
Crawley beat Hefield by two wickets, while Slinfold and Keymer & Hassocks drew.