WGC put themselves within one win of possible promotion with this victory, while two victories in their upcoming games, will seal a SSML Premier place for next season.
But in the opening half of this encounter with third bottom London Lions, the Citizens looked anything like a promotion side.
They were frankly, surprised by the vim and vigour of the youthful Lions, who deserved to be in front at the interval, only finding themselves level thanks to a 45th minute equaliser.
There was clearly a hangover from WGC's lack-lustre defeat to neighbours Hatfield the previous Saturday, as Adam Fisher's side, lacking the injured Liam Kenna and suspended Jack Dekanski in defence, showed no cohesion and barely put together a decent move in the opening half.
In contrast, Lions were eager and enthusiastic and striker Lior Sidle shot over the WGC woodwork and Adam Lipman, had a shot blocked in the opening exchanges.
Charlie Kasler then brought WGC keeper Joe Croft to a diving save Sidle putting the rebound over, before Kasler struck the WGC woodwork on the half-hour mark.
So it was totally undeserved, when WGC took the lead in 33 minutes, in one of their few dangerous moves of the half, Sam James, who had a very industrious return to the line-up, drove forward from 25 yards out and struck a low shot that went in under Lions' keeper Mario Cenolli's body, for the opening goal.
Lions were angered minutes later, when they clearly thought they had netted the equaliser, Omri Brinner's shot from 20 yards wrong-footing Croft, but referee Cushen ruled that Sidle was 'interfering with play', even though he didn't touch the effort on its way in.
The visitors did deservedly level on the stroke of half-time, when Kasler got away. Croft parried his initial strong shot, but the ball went back to Kasler, who drove home the rebound, powerfully into the far corner.
WGC still struggled in the opening quarter of the second-half, until Jason Caswell, was introduced on the hour mark.
Within two minutes of coming on, Caswell won the Citizens a penalty as he attempted to latch onto a rebound off the keeper from Joel Norris' shot. Keeper Cenolli pulled him down, but then redeemed himself with a fine full-length save from Norris' spot-kick.
The miss scarcely mattered, as two minutes later WGC were ahead again, thanks to a fine solo goal from Caswell, who picked up 30 yards out, slipped around two defenders and beat Cenolli with a low shot into the bottom corner.
From that point, it became a different game.
WGC's superior stamina and fitness seemed to really tell in the closing half-hour and 13 minutes from time an excellent third was created and scored by Sean Brettell, collecting on the left, switching passes with Daryl Smith, before driving a dipping volley beyond Cenolli for the clinching goal.
Moments later, Brettell almost had a second with a dipping free-kick that Cenolli turned away in fine style.
WGC introduced recent signing Mason Bush and the former Tottenham Academy product waltzed through, only to be stopped by Cenolli's feet. Three minutes from the end, Bush hit the Lions' woodwork with a shot that bounced back into the keeper's grateful arms.
There was still time for a WGC fourth, two minutes from time and again it was a finely created effort, James finding Brettell overlapping. He pulled back a cross that Norris controlled and struck home in one movement, as WGC closed the game in much more impressive fashion than they had begun it.
WGC: Croft, Perrin, Costain, Boodhoo, Brettell, James, Cifuentes (Ross 34), Smith, Arnott (C) (Bush 78), Arnott (M) (Caswell 59), Norris.