The first effort on goal came for Falkirk after six minutes when Blair Alston rifled the ball over from the edge of the box.
Falkirk took a 12th minute lead when good work by Sean Kelly set up Calumn Morrison at the back post and he buried a right footed shot low past home keeper Kevin Dabrowski.
It was nearly 2-0 when Conor Sammon's volley was clutched away by a stretching Dabrowski.A powerful long distance effort by Bairns skipper Gary Miller on 24 minutes fizzed not too far wide.
The Sons nearly levelled in spectacular style within three minutes when Robert Jones' fine overhead kick missed narrowly.
A speculative early second half effort from Dumbarton's Robert Jones flew over the bar.
It was 2-0 Falkirk on 48 minutes when brilliant set up play between Alston and Akeel Francis set up Morrison to emphatically shoot home his second.
Francis had a log range effort deflected over on the hour mark.
It was 3-0 on 73 minutes when Sammon knocked the ball home after a corner from the right flank.
The Bairns then added further gloss to the scoreline when substitute Anton Dowds tapped in from close range to make it 4-0 after the nippy Morrison had broken free in the penalty area and struck a low shot against the far post.
Ross Forbes had a free-kick comfortably saved by visiting keeper PJ Morrison before Charlie Telfer tested substitute Sons keeper Chris Calder with a shot which he turned round the post.
Falkirk are now in the running to qualify for the last 16 as either grup winners or one of the four best runners-up.
Falkirk: PJ Morrison, Dixon, Hall, Miller, Todd, Alston (Gomis 64), Francis (Dowds 64), Leitch (Telfer 64), Sammon, Kelly, C Morrison.
Referee: Scott Lambie