The race for the runners-up spot will go down to the wire after Broadwater and Arundel both suffered disappointing results.
Broadwater lost by five wickets at Lindfield after being restricted to 172-9. Joe Owen (50) and Richard Luker (48) top scored, while Dave Parry took 4-41.
Lindfield reached the target thanks to a fifth-wicket partnership of 108 between Azhar Ali (56) and Graham Page (44 not out).
Arundel only picked up a point from a draw at Ifield, Will Clark making 62 as the visitors posted 164-8, before Ifield held on to close on 56-3.
Bottom club Goring enjoyed their second win of the season at Pagham, who were dismissed for 143 with Mark Hoare making 47. Rob Hemmingway helped Goring to 147-9 despite the best efforts of Craig Primmer (7-27).
The division two title will be decided on the final day of the season.
Leaders Ansty remain a point clear despite losing by three wickets at home to Crawley Eagles.
Paul Osborn scored 41 as Ansty set a target of 188-7.
It looked enough as Eagles struggled to 78-6, before they reached 191-7 with five balls to spare thanks to 47 not out by Faisal.
Second-placed Keymer and Hassocks failed to take advantage as they were held to a draw against Barns Green. Michael Johnson hit 59 as Keymer chalked up 165-9, but Green survived to make 141-8.
Billingshurst moved to within seven points of the leaders after dismissing relegated Clymping for 67 in a five-wicket win.
Andy Welfare (6-28) did the damage, before Jason Rigby made 43 in reply.
Crawley posted 211-8 in a draw against Scaynes Hill, who finished on 126-8 with Craig Paterson (42) top scoring and Paul Clifford taking 6-47.
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