Billy Kee nodded the hosts in front just before the break, and Matty Pearson rose tallest to head home a Sean McConville free-kick to seal the defear for Danny Webb’s side.
McConville got himself on the scoresheet to make it 3-0 seven minutes from time, and then he scored from just inside the O’s half on 85 minutes. Pearson doubled his tally in stoppage time to compund the O’s woes.
Orient made one change from the side which lost 3-0 at home to Grimsby Town on Saturday with Gavin Massey returning following his two-match suspension, while Steven Alzate dropped to the bench.
It was a positive start from the O’s who had all the early pressure inside the opening few minutes and the returning Massey saw a shot well held by Marek Rodak.
Rodak then launched a swift counter attack for the hosts and his opposite number Charlie Grainger was forced into his first action of the game when saving well from Jordan Clark.
The home side built on that and the ball fell kindly to Seamus Conneely on the edge of the box but his shot was just wide of the post with Grainger at full stretch.
It was certainly a lively opening and Orient went straight up the other end and Massey fizzed an effort just wide as both side’s showed their attacking intent early on, while Dalby headed a great chance straight at Rodak.
The hosts missed another golden opportunity as a ball in from Harvey Rodgers found McCartan unmarked in the box but he shot agonisingly wide of the target in the frenetic opening passage to the game.
Only a last-ditch tackle from skipper Nicky Hunt denied McConville a shot on goal, but the defender was injured in making the challenge. While off the pitch McConville delivered a free-kick into the box and Omar Beckles headed wide.
Just after the half hour mark Beckles once again went close with a header as the hosts began to turn the screw. More last-ditch defending from a combination of Hunt, Judd and Massey kept McConville quiet and Orient launched a swift attack.
It came through Koroma and after a mazy run where he jinked one way then the other before seeing his shot deflected into the arms of Rodak.
Massey was certainly causing problems and on two occasions he went down in the box, but referee Graham Salisbury waved both appeals away.
Hunt was forced off with the injury he suffered early in the half, and was replaced by Teddy Mezague.
And from the set piece nobody picked up Billy Kee and the striker headed home to give the hosts the lead with a minute remaining in the half.
The first opportunity in the second half came the way of the visitors and it was a great ball through for Myles Judd and his delivery into the box was just met at the near post by Rodak ahead of Dalby.
Grainger was then forced to tip over a header from Kennedy as Stanley won two corners in quick succession, though nothing came of either dead ball situation.
And it was a set piece from which the hosts doubled their lead on 51 minutes when McConville’s lofted free-kick found the head of Matty Pearson and he directed it past Grainger.
Koroma was almost able to punish a sloppy Accrington misplaced pass but after working it on to his right foot he saw his effort smothered by Rodak.
Orient won only their second corner of the game on 65 minutes and although the initial set piece came to nothing, Massey popped the ball back into the box and Parkes, at full stretch, headed over.
Koroma curled an effort into the arms of Rodak after the ball was played into his path with a nice lay-back from Liburd.
Every time Stanley put a ball into the box the O’s looked in danger of conceding though and only a goaline clearance from Kennedy denied Beckles from another set piece.
But it was to become 3-0 with six minutes left as despite a Callum Kennedy block the ball fell to McConville and he curled an effort into the top corner.
And a minute later it was that man McConville who added further woe to the O’s when trying his luck from the halfway line and the effort struck the underside of the bar and into the back of the net off of Grainger.
Stoppage time saw the hosts add a fifth and it was a second for Pearson as he slid home to round off a difficult night for the O’s.
ACCRINGTON STANLEY: Rodak, Rodgers, Beckles, Hughes, Pearson, Clark (Shaw 87), Brown (Husin 76), Conneely, McConville, Kee, McCartan (Edwards 82).
SUBSTITUTES: Gornell, Boco, Hewitt, Chapman.
GOALS: Kee (44), Pearson (51, 90+2), McConville (84, 85)
LEYTON ORIENT: Grainger, Judd, Hunt (Mezague 43), Parkes, Kennedy, Collins, Moncur (Atangana HT), Koroma, Massey, Semedo, Dalby (Liburd 53)
SUBSTITUTES: Sargeant, Alzate, Clark, Abrahams.
BOOKED: Kennedy (11), Collins (51)
REFEREE: Graham Salisbury.
ATTENDANCE: 1,306 (198 Orient fans)