The Blues returned home after what had felt like an age on Saturday afternoon for game number four of the league season.
And the starting eleven was unchanged again following what had been a solid and unbeaten start to the campaign.
The only change to the bench was forward Gime Toure stepping up in place of Taylor Charters.
United kicked off heading towards the Warwick, and a bullet of a throw from Riley with just 44 seconds on the clock earned his side a corner as Happe put it behind to safety.
A rushed piece of play across the Orient back line, thanks to pressing from Abrahams, had Vigouroux hurried in the clearance but he had luck on his side as his kick just about made it past the onrushing Alessandra.
The Blues were awarded a penalty on seven minutes when Mellish was tenacious down the right wing. A block tackle spun up off his boot and angled towards Abrahams, who had Beckles in front of him on the edge of the area. A clever clip hit a raised hand, and the referee immediately pointed to the spot. Abrahams placed it and smashed a beauty of a rifled dead ball into the roof of the net.
Excellent defending from McDonald saw him bring an end to a long run from Archibald as the winger skipped free on the left flank. Strength and timing were the key ingredients.
Archibald was the visiting outlet once more as the O's came again and his cross had to be watched closely by Norman, who came off his line to gather low.
United attacked from the distribution and Abrahams was suddenly in the clear as Happe misjudged the ball forward. He crept along the byline and Vigouroux had to punch it away as the shot came in sharply.
It was recycled by Alessandra, and Abrahams was on the move again. His backheel had just too much on it for Armer and an attempt at a reverse pass to Mellish from just inside the box was cut out.
Guy started to pull some strings in midfield and a spinning pass to Dickenson was followed by a lovely delivery from the winger. That was cleared, but Dickenson was there again as he was fed through by the same player. Another wicked cross had to be dealt with.
The home crowd were enthused and noisy as every 50:50 challenge went the way of the boys in blue, and a swift move down the attacking left saw Abrahams get involved once more. His movement took him away from his man, but a low pass was an inch behind Alessandra.
McDonald then almost picked the perfect pass for Dickenson from deep, but the touch off the chest was difficult and the keeper was able to claim it.
Carlisle stayed on top and a switch from left to right put Tanner on the overlap. He was chopped at the moment he crossed and a free kick was given tight by the byline, just beyond the 18-yard line. Guy swept that low but it was cleared after Alessandra had touched it on.
Orient were given no time to breathe as the ball was swung back in. Dickenson thought he'd scored with a downward header from eight yards out but Vigouroux dived low to palm it away before it could cross the line.
Having controlled the first 45 minutes, United looked for more of the same as they came out for the second period.
Orient boss Kenny Jackett went for a double substitution, with Ogie and Smith on for Sotiriou and Sweeney, and Smith was involved immediately as he tried to get into the area. His shot was blocked and the home defence cleared.
Carlisle broke with Joe Riley on the ball, and he surged on from his own half directly towards the box. He shot from range but he couldn't keep it down.
Another move sparked by strength from Mellish as he rode two challenges put Dickenson in space. His cross was about to be put away by Alessandra until Happe got the slightest of touches.
Substitute Harry Smith nodded well wide at the other end when he was found by Pratley, and a game with real flow saw Dickenson put one right at Vigouroux when he was worked into space by Alessandra and Mellish.
Dickenson then had a shot on the run spoon up off the boot of Tom James, with the stopper able to pluck it out of the air before it dropped behind.
McDonald did well to track an overlap from James which spelled danger, and the reward was a great interception that prevented Smith from snaffling up an easy chance. Norman was out to claim the corner inswinger with a strong leap.
Riley dragged one wide as it opened up in front of him just after the hour, and superb control from Clough saw him send the same person through as the Cumbrians broke. Vigouroux was out quickly to scoop it up.
There was the same from Norman at the other end when a flick from Smith invited James to steam in. The keeper was fully committed as he got there first.
Pace from Tanner brought him into the attack after Dickenson had spread the play to Alessandra. The pair exchanged short passes before the striker bent his curler wide.
Orient equalised from nowhere on 74 minutes when a ball over the top was cleared on the slide by Whelan. Archibald snapped it up, and his cushioned through ball allowed Smith to dink it over Norman into the bottom corner.
Norman dived long to make an excellent two-handed save from Archibald when he let fly from 23-yards, with the away side looking to hit the big front men quickly, but chances were hard to come by as both teams defended with concentration and determination.
A sprint from Toure brought a late challenge from Clay deep into time added on, and Clough sent a fizzed ball at the front stick. Mampala jumped, but he didn't quite get the touch it needed and Vigouroux held onto it as he fell to the floor.
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Carlisle United - Abrahams (8 pen)
Leyton Orient - Smith (74)
Leyton Orient - Sweeney (17), Smith (55), Drinan (61), Kyprianou (65), Clay (90)
Carlisle United - Norman, Tanner, McDonald, Whelan, Armer, Riley, Guy (c), Mellish (Clough 66), Alessandra, Abrahams (Mampala 83), Dickenson (Toure 88). Subs - Jensen (gk), Feeney, Bell, Young.
Leyton Orient - Vigouroux, James (Clay 75), Happe, Kemp, Archibald, Drinan, Pratley, Beckles, Sotiriou (Smith 46), Sweeney (Ogie 46), Kyprianou. Subs - Byrne, Wood, Omotoye, Nkrumah.
Referee - Robert Madley
Assistant Referee 1 - Graeme Fyvie
Assistant Referee 2 - Richard Woodward
Fourth Official - Simon Mather
Observer - Brian Parry
Attendance - 4,597 (259)