Gavin Massey gave Webb the perfect opening when netting after 25 minutes, though Gary Liddle levelled nine minutes later as the first half ended 1-1.
But it wasn’t to be for the O’s as Jamie Proctor’s headed effort put the Cumbrians in front, and despite his sending off, the O’s lost out.
Orient made four changes to the side which lost 2-0 at Mansfield Town with Sam Sargeant coming in for his first league start of the season in place of Alex Cisak, while Myles Judd, Nigel Atangana and Rowan Liburd also came in for Teddy Mezague, Sammy Moore and the injured Paul McCallum.
There was a positive mood around the ground from the off and within the opening two minutes the O’s forced a corner after Massey’s cross was deflected behind.
Former O’s loanee Nicky Adams was the main threat for Orient in the first half, dictating most of the Carlisle chances, though Ibehre fired well over the North Stand and Michael Raynes headed wide of the target.
With 25 minutes on the clock the O’s were in front though as they capitalised on a Carlisle error. Massey intercepted and he was able to run through on goal before blasting a ball underneath the dive of Gillespie and the Matchroom Stadium was rocking.
Adams continued to be the thorn in Orient’s side and he curled another effort wide, before the Cumbrians drew level with 34 minutes on the clock.
Sargeant had done well to push Jamie Devitt’s shot on to the bar, but Liddle was quick to rebound and he slotted home.
Orient were not deterred by the leveller though and remained positive. Another run from the impressive Massey resulted in the winger putting a ball into the box, but Liburd or Dalby were unable to get on the end of it as the half drew to a close.
No changes were made at the break by either side and it was the visitors who created the first opportunity of the half on 49 minutes.
The ball feel invitingly for Ibehre who had beaten the offside trap but Sargeant was alert and deflected the effort behind for a corner.
Massey went on yet another rampaging run across the box and he played in Dalby, who showed great retention of the ball to remain in possession. He played the ball back into the path of Massey whose shot was blocked.
However in the most unfortunate of circumstances the O’s trailed. Sargeant did superbly well when going the opposite way to deny George Waring’s header. Unfortunately the ball fell straight to Proctor and he was left with the simple task of slotting into an empty net.
Proctor went from hero to villain soon after though as shortly after receiving a yellow card for a foul in the corner, he went in two-footed on Sammy Moore and referee Graham Horwood gave the striker a second yellow.
Victor Adeboyejo was brought on to replace Sam Dalby just after the dismissal.
O’s pushed forward and Judd saw a shot blocked after a Kennedy cross was half cleared, before Moore let fly from 25 yards but his effort was comfortable for Gillespie in the Cumbrians goal.
Kennedy was forced off through injury, and was replaced by Teddy Mezague.
Five minutes of stoppage time was announced and within the opening minute Atangana got a clever flick on Semedo’s dangerous ball in, but it was over the bar.
ORIENT: Sargeant, Kennedy (Mezague 83), Parkes, Hunt, Judd, Semedo, Atangana, Collins, Massey, Dalby (Adeboyejo 77), Liburd (Moore 60).
SUBS: Grainger, Kelly, Koroma, Erichot.
GOALS: Massey (25)
BOOKED: Hunt (45), Massey (68).
CARLISLE: Gillespie, Liddle, T Miller, Raynes, Gillesphey ,Joyce, Devitt, O’Sullivan (Jones 69), Adams (Bailey 85), Ibehre (Waring 66), Proctor.
SUBS: Crocombe, Lambe, S Miller, McQueen.
GOALS: Liddle (34), Proctor (68).
BOOKED: Proctor (74)
SENT OFF: Proctor (76)
REFEREE: Graham Horwood
Attendance: 4,306 (677 Carlisle United fans)