Swaffham Town cranked up the pressure on Thurlow Nunn Fist Division North leaders Harleston with a big win.
The Pedlars thrashed Ipswich Wanderers 6-1 away to move up to second spot on a day when they were the only one of the top three to play.
Victory means Swaffham are now five points ahead of third-placed Mulbarton Wanderers and two behind Harleston – and with a game in hand.
Joe Jackson opening the scoring at Ipswich in the 11th minute, played through by Callum South and slotting past the keeper from 12 yards.
Ryan Pearson made it 2-0 five minutes before half-time, heading Danny Tindall's free-kick against the bar but following up to net the rebound with a header from six yards.
Jackson scored the goal of the game as time was being called on the half, played through by Kyle Plumb and lobbing the keeper from 12 yards out. Luis Duarte made it four on the hour, volleying in across goal into the right-hand corner.
A lack of concentration let Wanderers back in with a goal in the 63rd minute, but Jackson completed his hat-trick two minutes later, cashing in on a poor clearance and lashing the ball home.
Ben Coe closed the scoring in the 69th minute after coming on as substitute for Duarte just five minutes earlier, played through on the left and finishing from 14 yards across goal into the right hand bottom corner.
Elsewhere, Downham Town beat visiting Cornard 2-1.
In the Premier Division, Great Yarmouth Town's hopes of survival suffered a blow when they were beaten 3-0 away to FC Clacton.
That dropped them a place to third from bottom, below Ely who, despite not playing, have a better goal difference.
Kirkley & Pakefield won 1-0 at bottom side Long Melford,
Norwich United were 3-2 winners away to Godmanchester Rovers with two goals from Liam Jackson and one from Craig Bussens.
Bostik North
Dereham gained a useful 3-2 away win on a difficult pitch at Witham. The struggling hosts took the lead after just five minutes when Situ Odelusi bundled home Johnny Ashman's cross from the right from close range. Things nearly got worse for the Magpies when Ashman cut in from the left and struck the far post before Jack Lelliott picked up the loose ball and hit the top of the bar.
Dereham levelled from the penalty spot after 15 minutes after Ryan Crisp was pushed and Adam Hipperson made no mistake from the spot. Danny Beaumont tested Luca Collins with a long-range effort and then flashed a 20-yard volley wide.
Dereham went in front in the 43rd minute – the ball bobbled across the area and reached Crisp who turned sharply and beat Collins with a well-placed low drive. The Magpies increased their lead when Rhys Logan beat his man down the right and delivered a dangerous low cross that Beaumont nudged towards Crisp and the striker converted his second goal of the match from close range.
As Witham looked to bounce back, Shaun Wones produced a fine interception to block Luke Foster's shot on the turn and Odelusi fired over when well placed. They pulled one back in the 85th minute when Adam Plumstead brought down Foster in the box and Odelusi converted to set up a tense finish.
Anglian Combination
Caister returned to the top of the Premier Division on a day when their nearest rivals were without a fixture.
Goals from Nick Bailey, Dan Burgess and Jordan Stanton earned them a 3-1 win at Hellesdon, whose scorer was Ross Pantry.
It gives them a one point advantage over Sheringham who have two games in hand, with Long Stratton a further three points back with just one game in hand on the leaders.
Bryn Mullin scored all the goals in Wymondham's 3-0 win at Norwich United Under 21s, while Luke Bailey scored twice as Beccles beat Acle 5-1. Jordan Boyd, Tom Palmer and Rob Fisher also scored, with Sam Brookes getting Acle's consolation.
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