City showed they were up for it in the first minute when a great ball from Ben Burgess nearly played in Jon Walters, but Glen Morris raced out of his area and made a desperate lunge to kick it away.
After 10 minutes Burgess shot wide, and two minutes later Stuart Elliott hit the side netting after a great cross by Jason Price on the right wing who did well to sneak behind the defence.
After 17 minutes, Walters' flicked header found Burgess, who toe poked the ball a foot wide of the right post with Morris beaten.
City took the lead after 20 minutes after Walters spotted an opening and slotted a perfect ball to Elliott, who raced down the left wing and beat the advancing Morris with a clinical strike from 18 yards.
The play was all City, with Orient struggling to get into City's half, but after 30 minutes ex-Tiger Gary Alexander managed two wayward shots.
After 56 minutes Burgess whipped in a cross from the byline and if it had not been for Tom Newey's interception at the near post it would almost certainly have been a goal for Price who was lurking yards out.
After 63 minutes a terrible back pass by David McGhee let Burgess in, who seemed certain to score after winning a challenge with Morris but John Mackie got back well to intercept.
Two minutes later Orient exploded into life with three corners in succession, after Jabo Ibehre had stunned City with a shot which Burgess cleared of the line.
On 78 minutes, City doubled their lead after Ian Ashbee teed up a perfect cross to the unmarked Burgess, who planted an unstoppable header from 12 yards.
Ryan France completed the victory in injury time, nodding in at the far post from Stuart Green's cross.