Lloyd James gave Orient a 22nd minute lead from the penalty spot after Paul McCallum was fouled, before Jay Simpson added another in first half stoppage time as the O’s brought an end to Bristol Rovers 20-match away unbeaten run in the league.
Going into the O’s sat firmly at the top of League Two and Ian Hendon continued with the same starting XI for the fifth successive league fixture.
Furthermore, the O’s Head Coach made only two changes to the substitutes bench as Alan Dunne returned from injury while loan signing Joe Maguire was also included for the first time having joined from Liverpool on Friday.
Following a tight start to the match Orient came close from a set-piece as Dean Cox’s delivery was deflected just over the bar for a corner.
Minutes later however O’s goalkeeper Alex Cisak, playing in his final match before joining up with the Australia national team on Sunday, was called into action as he produced an impressive one-handed save to parry away Ellis Harrison’s low attempt.
The match was proving a fierce contest early on as Orient looked to counter the visitors 3-5-2 formation with a 4-5-1 that saw Cox and Simpson operate on the flanks.
Despite the tight opening exchanges the O’s were then presented with a chance to make the breakthrough from the penalty spot.
Paul McCallum had seen a number of decisions go against him but when Pirates defender James Clarke pushed him inside the area, referee Darren Drysdale had little choice but to award the spot kick.
Midfielder Lloyd James stepped up to take the resulting spot-kick and made no mistake as he calmly rolled the ball to the right, sending Rovers goalkeeper Aaron Chapman the wrong way in the process.
Having taken the lead the O’s struggled to create any further openings but as half time approached, both sides were presented with another chance.
The first was to drop to the visitors as they nearly capitalised on Cisak’s failure to punch away Chris Lines’ free-kick, but Orient captain Mathieu Baudry was on hand to superbly block Tom Lockyer’s shot behind for a corner.
In stoppage time Orient were to go one better however as they doubled their advantage through Simpson.
With the ball out on the left Cox floated a pass across to Simpson who brought it down well on the edge of the area, before wriggling some space and sweeping the ball into the bottom corner to make Ian Hendon’s half-time team-talk that little bit easier.
During the interval Hendon was forced into making a change though as Alan Dunne replaced Baudry who was struggling with a knee injury meaning Sean Clohessy skippered the side for the second half.
Having found the back of the net Simpson was then presented with two chances in quick succession as he first saw a flick from a James’ pass held before Chapman got down low to keep out a low attempt.
Not shirking his defensive duties the O’s striker then put in a brilliant last-ditch challenge to prevent Lee Brown as he charged up a shot inside the penalty area.
As Rovers looked to get back in the tie Cisak was tested as he first pushed away Jermaine Easter’s drilled attempt before instinctively getting a leg to Ellis Harrison’s follow up.
A change in formation for the visitors saw Orient also revert to a 4-4-2 as the second half and midfielder Bradley Pritchard wasn’t far from adding a third when his shot from outside the penalty area took a slight deflection to go wide.
With 20 minutes remaining Tom Parkes then squandered a wonderful chance to pull a goal back as he could only flick Brown’s free-kick the wrong side of the post from less than six yards out.
Parkes' defensive partner James Clarke then wasted an even better opportunity in the dying minutes following a corner but the centre half could only blaze his shot over the bar in what proved to be the final chance of the match as Orient registered their fifth consecutive win and become the first side to claim a home victory against Bristol Rovers in nine months.
ORIENT: Cisak, Clohessy, Baudry (C) (Dunne HT), Essam, Shaw, James, Pritchard (Turgott 79), Moore, Cox, Simpson (Palmer 70), McCallum
SUBS: Grainger, Maguire, Moncur, Kashket
GOALS: James (23 pen), Simpson (45+2)
BOOKINGS: Pritchard (11), James (28)
BRISTOL ROVERS: Chapman, Lyttle (Monakana HT), J Clarke, Lockyer, Parkes, Brown, O Clarke (Montano HT), Lines (C), Sinclair, Easter (Taylor 61), Harrison
SUBS: Mildenhall, Mansell, Gosling, Bodin
Referee: Darren Drysdale
Attendance: 5,777 (1,023)