The O’s made five changes from the side that lost 2-1 to Barnet at the weekend, top-scorer Jordan Adeyemi coming back into the team as he continued his return from injury.
The hosts had the early possession, the first chance falling after 16 minutes when a wavy Ayoub Assal run found Dylan Adjei-Hersey at the corner of the box, his side-footed effort flying wide of Campbell’s goal.
They found the back of the net just five minutes later when the ball was prodded to Assal in the box, the diminutive forward smashing into the roof of the net.
Assal was at the centre of the action once again after 36 minutes when he went over under the box but the referee felt it was simulation and booked the AFC Wimbledon man.
Lawrence Hammond, who has eight goals this season, had an effort on goal from distance two minutes later but the AFC Wimbledon ‘keeper was level to it.
The O’s looked better in the second half as Antony Papadopoulos lifted an effort wide just after the break, although Campbell was required to make a good save from Zach Robinson.
It began to feel that the next goal was vital and unfortunately for the O’s it fell it the home side, Dylan Hersey’s cross finished by Robinson at close-range.
The AFC Wimbledon forward netted his second after 66 minutes, as a corner wasn’t cleared and he was there to smash home.
David Fisher wrapped up the tie with a lovely strike ten minutes before time as his left-footed curling effort nestled in the bottom corner.
Lawrence Hammond had the opportunity to pull back a consolation when he nicked the ball from a home defender but Matthew Cox in the Dons net made a great save.
Sean Campbell made a number of good saves in the latter stages of the match but there was nothing he could do about the fifth, a corner volleyed home by Jack Madelin.
LEYTON ORIENT: Campbell, Papadopoulos, Sweeney, M. Young (Mirza 68), Marfo, Francois-Vernal, Sivi (Mothersille 68), McLenaghan, Hammond, Lovatt (Ifeanyi 77), Adeyemi
SUBS: Dunbar-Bonnie, Frempong, Solomon, J. Young
BOOKED: Papadopoulos (24’)