Hitchin and Letchworth continued their winning ways with two equally impressive performances.
Letchworth's 16-10 win away to HAC keeps them seven points clear of Eton Manor in Regional Two Anglia but Southend Saxons' loss to Woodford means they are now just nine points away from promotion.
Josh Sharp kicked 11 points with the only try being scored by Sonny Ma'asi.
All nine points in the first half were scored from penalties, Sharp landing two of them to give the Legends the narrow lead.
Both sides had chances to add a try to their tally.
A good tackle from Will Titherington prevented HAC from getting one score and Adam Amos and Ma'asi stopping another attack.
Sharp's second penalty came after Luke Mongston's quick thinking was stopped illegally, earning the offender a yellow card.
An interception should have given Letchworth an even bigger lead earlier in the second half but a handling error ended that move.
However, it was a temporary reprieve and better hands from the backs allowed Ma'asi to power over close to the posts.
The 10-point lead though was back down to three within moments as HAC scored a converted try but with less10 minutes to go, Sharp landed another kick to put Letchworth six ahead.
It meant HAC could snatch it with another converted score and they were given a boost when Titherington was sin-binned.
And the hosts went close, but a huge hit by Ma'asi and then a big steal gave Sharp the ball and he launched it from the field to give Letchworth the win.
Hitchin's dazzling late season form shows no sign of stopping as they made it three wins from three at Welwyn.
The Hedgehogs went into the game on the back of two fine successes, both with a winning margin of more than 30 points and both having scored between 40 and 50 themselves.
This was almost a carbon copy as they sauntered to a 41-10 victory to pull themselves clear in fifth place in Counties One Herts Middlesex.
Hitchin were on the front foot from the outset and territorial pressure told as Welwyn conceded penalty after penalty.
Fly-half Ben Wiggins kicked three of them over the crossbar to hand the visitors a 9-0 lead inside 15 minutes.
The hosts' first real venture into the Hitchin half proved fruitful though.
A penalty of their own was kicked to within 10 metres and although the initial attack was stopped, the pack pushed their way over from a five-metre scrum.
It was the only score they would get in the first half as Hitchin quickly got their hands on the ball and applied plenty of pressure through exciting play.
A line-out led to their first try, Elliot Gibson and Ruiri Shanahan combining for the latter to draw the Welwyn defender and slip the ball out to Jack Maydom for the score in the corner.
Two minutes later, Hitchin struck again.
This time it was a piece of individual brilliance from skipper James Bolter who collected a Shanahan pass out of contact, chipped over the rushing defensive line, before collecting the loose ball and sprinting 30 metres under the posts.
There could have been a third but a knock-on inside the Welwyn 22 removed that chance, however, Hitchin still turned round with a 21-5 lead.
Ian Crompton and Phil Ryan began the second half with 20-metre bursts but the first points came from the boot of Wiggins as he kicked his fourth penalty close to the posts.
Ryan narrowly failed to touch down a grubber kick from the 10 but from the subsequent 22 drop-out, Maydom collected the ball on halfway and surged through two forwards and around the full-back for a sensational try.
The bonus-point score came after Nick Panton had fielded the kick-off and given it to Fred Rooney.
From the next phase Crompton proved as elusive as Maydom had but he gave the scoring pass to Ryan.
A high-tackle earned Jack Sibley a 10-minute sit down and it also allowed Welwyn to add a second try.
But the visitors would have the final say and after Simon Taylor wrestled through three tackles to make vital yards, Wiggins threw a miss-pass to Jon Welsford who finished well from 10 yards.
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