The hosts took the lead after 20 minutes when Mike Booth steered the ball wide of Sheldon Levett in the Seaford goal, but Town levelled a minute before the break thanks to a superb left-footed strike by Alex Thompson.
Chances were few and far between during the second period, but Westfield won it with just eight minutes left on the clock. A free kick was played to the far post where it was headed back for Sam Henham to poke the ball home.
It was one of only four senior matches to go ahead in the Sussex County Football League on Saturday and much of the credit for that must go to groundsman Jon Attewell. Westfield move above neighbours Bexhill United into seventh place in Division Two.
Bexhill, Little Common, Rye United and Sidley United all had their games called-off, although Sidley’s scheduled visit from Lancing has been rearranged for this Thursday night, replacing the scheduled Hastings & District FA Senior Cup semi-final against Bexhill.
Sussex Division Two top half (played-points): 1 Newhaven 26-58, 2 Littlehampton Town 23-55, 3 Eastbourne United AFC 25-49, 4 Broadbridge Heath 25-46, 5 LITTLE COMMON 24-45, 6 Midhurst & Easebourne 24-43, 7 WESTFIELD 25-40, 8 BEXHILL UNITED 25-38, 9 Loxwood 24-36.