THIS much anticipated derby - the first for five seasons between the clubs - saw the Citizens win a five goal thriller to stretch five points clear of their local rivals with a game in hand.
A bumper holiday crowd of 354, just nine short of a Herns Lane league record, filled the ground to see Adam Fisher's side deserve the vital three points available here, in a victory that could have been more emphatic, but for the agility of Hatfield's giant keeper and captain Allan Buck.
WGC now lead the table by three points going into the new year, Bedford FC having won a seven goal thriller of their own, now splitting the sides, but having played three more games than the Citizens.
WGC got the perfect start with a goal in five minutes. Sean Brettell began the move on half-way and almost finished it himself. He found Craig Arnott and then got onto the end of Arnott's pass to bring a diving save from Buck, who pushed it away but couldn't hold and Marc Arnott rammed in the rebound.
Hatfield responded immediately, the powerful Ben Alexander driving a good effort just over Joe Croft's crossbar.
Back came the Citizens and Craig Arnott and Brettell were involved again, playing in Joel Norris, but a poor touch allowed Buck to save at his feet.
Norris did better with a fierce drive just past a post after a Jason Caswell pull back from the by-line, before WGC doubled their lead just before the half-hour. From a Sam Perrin left-wing corner, Daryl Smith rose highest to net with a downward header past Buck.
Buck showed outstanding agility with he tipped over an on-target header from Norris 10 minutes from the break, but in the closing period at the end of the half, the game was turned on its head.
Five minutes from half-time, Hatfield were back in the game, when a rash challenge from Caswell helping defend a corner, tripped Hatfield's Gary Sippetts and referee Walshe had little option but to award a penalty. Ben Collins just beat Croft's dive with his spot-kick into the corner.
Two minutes later, the visitors were level. This time, left-winger Steve Harper was given too much time and space to whip across a dangerous centre, Croft managed to tip it away, but in the ensuing scramble, Aaron Lewis drove in a firm equaliser to stun WGC and tie the scores at half-time.
To their credit, WGC recovered their composure over the half-time break and came out all guns blazing at the start of the second period.
Buck showed more agility with another fine save to push over a header from the outstanding Yasin Boodhoo three minutes after the restart.
But WGC wouldn't be denied. From the resulting corner, Boodhoo again got his head to it to divert it out to Craig Arnott who returned it to the area, where Norris came in to plant another good, downward header beyond Buck to restore the lead.
Hatfield broke out briefly for Lewis to go clear and provide a good cross that Sippetts drove wide, but the second-half was largely a tale of WGC pressure and defiance by keeper Buck.
He made a fine block when Caswell got through one-on-one with the keeper and then was rescued by defender Robertson who got Marc Arnott's rebound effort off the line.
Daryl Smith made a strong run down the right to find Caswell, who produced the moment of the match, to turn excellently between two defenders, only to blaze wide with the goal beckoning!
Caswell was again denied when Hatfield defender Williams slipped in the muddy conditions and the WGC striker got clear on goal, but keeper Buck again fingertipped the effort over, as he continued to deny WGC more than a goal advantage.
WGC picked up late bookings for Craig Arnott & substitute Bradley Jenner, but they couldn't take the gloss off what could prove a crucial derby victory.
WGC: Croft, Perrin, Boodhoo, Kenna, Brettell, Arnott (C) (Cifuentes 79), Stellon, Smith, Arnott (M) (Jenner 87), Caswell, Norris (James 67).