Jamie Milligan made three changes for the clash at the Sir Tom Finney Stadium to the side that lost at Scarborough last weekend, with Joe Booth, Green and Waddecar coming into the XI in place of Chris Churchman, Rowan Roache and the injured Matt Dudley.
With an attendance figure of 1,014, the atmosphere was electric from the get go and Booth put in a crunching tackle in the opening minutes to dispossess an on-rushing Michael Potts.
Then, with their first clear cut chance of the game, Brig took the lead.
George Thomason received the ball in midfield before lifting a through pass over the defence to find Waddecar, who made no mistake in placing the ball beyond FC United goalkeeper Cameron Belford.
Richie Allen then came close with a left-footed effort from close range that was closed down by Belford.
Down the other end, Callum Spooner did well to clear off the line after league top scorer Tunde Owolabi had lifted the ball over Danny Roccia.
Brig then had a big shout for a penalty turned down when Allen went down in the box, before Belford kept out another effort from Brig’s number 11.
Milligan’s side were continuing to put the pressure, and Allen narrowly failed to connect with Green’s low cross across goal on 30 minutes.
Green himself then had an opportunity on 37 minutes, breaking the offside trap and rounding the ‘keeper but was unable to hit the target after the ball hit a bobble on the way through.
Brig entered the half-time interval deservedly in front, and had to soak up some early pressure in the second as the visitors began to push forward.
Substitute Morgan Homsom-Smith had a fierce effort from distance pushed over the bar by Roccia, before fellow sub Jack Lenehan fired over after a driving run.
Arguably the key moment of the game to this point came on 69 minutes, Owolabi finding himself one to one with Roccia inside the box only to be thwarted by a great save from the Brig stopper.
Down the other end, Brig extended their advantage four minutes later when Green latched onto an aerial through ball with his first touch, before poking the ball past the goalkeeper with his second.
Milligan then introduced on-loan Blackpool winger Nathan Shaw for his debut, and he capped off what was an impressive cameo display with his first goal for the club.
Allen played the 19-year-old through on goal and his shot had just enough power to go over the line before being knocked in by the FC defender who was attempting to clear.
With the score 3-0, the hosts continued to push forward in the late stages and Allen had another chance deflected out of play with three visiting defenders closing him down.
The full whistle rang out across the Sir Tom Finney Stadium, and with it came a thoroughly deserved three points for Brig.