Former strikers make the difference.
However, the U's will go again and look to start another unbeaten run against Dagenham on Tuesday.
The U's finished the game the stronger, but the O's remained resolute to keep the home side at bay.
The U's had levelled David Mooney's opener through Jabo Ibehre just before half time and had started the second half the brighter, but Kevin Lisbie's second half header was enough to confirm Orient's best ever start to the season.
Two goals from former Colchester United strikers proved to be the difference on Saturday, as Orient extended their unbeaten run whilst ending the U's own sequence of results.
Early on in the game, a darting Lisbie run saw him slide Mooney into the box and his low cross was turned past the post by Okuonghae. The corner saw the ball clip two players, but it went away to safety.
The U’s were looking dangerous themselves on the attack, with some timely tackles coming in handy for the O’s.
Watt was the first to get a sight of the O’s goal, turning sharply on the edge of the box after good work by Ibehre, to fire in a deflected shot that Jones snaffled up.
Watt had another chance on ten minutes, after more good approach play by the U’s. He set himself and curled in a fine effort that forced an acrobatic save out of Jones.
However, it was the visitors who took the lead after 14 minutes. A ball ran loose to Cox on the left who sent over a ball into the box for the onrushing Mooney.
The Irishman’s first touch brought the ball down into his path, his second saw him smash it past the helpless Walker.
The U’s responded well to going behind, with a series of set pieces to pin in the O’s. However, the visiting defence protected their keeper well to preserve the advantage.
One corner saw Eastman push his header wide, as the U’s drew closer, but the O’s were pressing the home side high up the pitch, preventing them their passing game going.
Chances remained at a relative premium but Lisbie sprung the offside trap on 28 minutes and forced a good stop out of Walker high to high left.
The O’s were clearly a side full of confidence, and strung the ball around nicely either side of the half hour mark in their quest for a second.
Walker was sharply off his line to deny Cox, and that save proved crucial when the U’s drew level eight minutes before the break.
Eastmond broke the midfield lines to burst towards the Orient box, and although he was blocked on the edge of the area, it ran to Ibehre to set himself and fire the ball home across Jones.
Watt then almost put the U’s in front two minutes before half time. Again he found space on the edge of the box, but his effort went just wide.
Level at the break, the U’s started the second half in lively fashion, but it was the O’s who had the first chance of note in that period.
Cox got to the byline and sent over a cross that Mooney met at the near post, but his glanced effort went across goal and wide of the far upright.
The U’s had their game going more in the second period, though, but fell behind again on 63 minutes. Cox was again the danger man, standing the ball up to the far post for Lisbie to power a header home.
It signalled a change for the U’s midway through the half, with Gilbey coming on for David Wright and Drey Wright coming on for Massey as the U’s added fresh attacking intent to the side.
Wright won a corner that almost allowed Okuonghae to get his first of the season, but his stabbed effort was deflected over.
The substitutions had given the U’s fresh impetus and, when the O’s failed to clear their lines on 73 minutes, Watt’s shot across goal was tucked home by Ibehre – who was quickly flagged offside.
Morrison replaced Sears with thirteen to go, and the experienced striker turned and fired narrowly over in another melee in the box.
Wright was the U’s main dangerman, though, and he twisted and turned Cuthbert all ends up before going down in the box. The fans and players were keen for a penalty, but the referee showed no interest.
The U’s were finishing the stronger against a side who had played 120 minutes in midweek, but couldn’t find the critical ball to test Jones.
Eastmond fired over after the ball broke to him on the edge of the box, before Walker went up for a corner late in the game.
The O’s broke through Batt, who shrugged off Olufemi but, with the goal at his mercy, he rolled his shot wide of the target.
That was the last chance as the U’s unbeaten record went in a game that had plenty of drama.