Orient ensured it stays tight at the top of League 1 as they returned to winning ways at Vale Park.
Goals either side of half time were enough to win it for the O's as Dean Cox set them on their way with a wonderful finish before Nathan Clarke grabbed his first ever goal for the O's from a Lloyd James corner in the second period.
It was not without the odd scare though as Vale twice had goals disallowed but Orient equally had further chances in a second half that was far livelier than the first in Staffordshire.
Russell Slade made one change from the team that drew at Meadow Lane on Saturday with David Mooney returning from a rib injury to start in place of Kevin Lisbie who dropped to the bench.
For the home side there was also just one change from the team which beat Carlisle at the weekend with Adam Yates coming into the side in place of Jack Grimmer, whilst Anthony Griffith lined up against his former employers.
The large playing surface at Vale Park was far superior to what the O’s experienced on Saturday but it was quiet opening period as both teams got to grips with each other, whilst Romain Vincelot and Griffith rekindled the midfield battle which saw them clash time after time in the return fixture in E10.
It took until the 11th minute before the first opening as Vale broke from an Orient free-kick and when Eldin Jakupovic uncharacteristically made a mess of a cross from the left, the ball fell kindly to Ben Williamson in the right channel but he dragged his shot wide.
The move seemed to give spark the home side into life as five minutes of pressure followed though Orient looked resilient despite struggling to retain the ball.
Slade was forced into a reshuffle midway through the half as Vincelot left the field with a limp following a firm but fair tackle from Griffith, with Marvin Bartley replacing him.
Bartley was straight into the thick of the action as Orient started to pose more of a threat going forwards with Dean Cox hitting a fierce drive into the side netting after good work from Mooney and Chris Dagnall on the 26 minutes mark.
Orient started to gain the upper hand as the half wore on as the width of the Vale Park pitch seemed to suit them and Lloyd James forced the first save out of Chris Neal with 10 minutes remaining of the first half.
The O’s soon made their dominance count and did so in style. Mooney gathered a James pass on the right and fed Odubajo who laid a ball across the face of the box for the arriving Cox to smash a stunning first time finish home off the crossbar to bag his 12th of the season.
Slade would have been delighted to head in with the lead, especially as his side still looked like they had plenty to offer going forwards whilst looking relatively comfortable at the back.
Orient started the second period looking more fluid than they had done in the first and Dagnall almost doubled their lead with three minutes of the half played when he picked the pocket of Carl Dickinson and skipped around the goalkeeper Neal but couldn’t quite turn the ball home.
The Valiants responded well though through a series of Jennison Myrie-Williams corners, the first of which was flicked to skipper Doug Loft at the back post who looked certain to score with a header but for James who pulled off a brilliant saving block on the line to deny him.
The game opened up as Mooney started to find space in front of the back four and it was Orient again who threatened from a Dagnall header after a neat move five minutes later but it wasn’t long before the O’s doubled their lead from an unlikely source.
James stepped up to take a corner from the right and it was met by the head of Orient skipper Nathan Clarke who powered a header home to score his first in a red shirt at the 79th time of asking.
Orient barely had time to catch their breath though before Jakupovic kept them two goals clear with a stunning save to deny Birchall who had found space inside the box to go one on one with the big Bosnian.
The O’s looked the more dangerous though as the 224 away fans sang their hearts out behind the goal. But it was far from plain-sailing for the O’s as Vale twice had the ball in the net only for them both to be ruled out, the first for offside following a scramble, the second for a foul. Whilst sandwiched in between substitute Billy Knott rattled the crossbar with an effort that Jakupovic appeared to get a fingertip to.
Still Orient could have well and truly killed the game though with 10 minutes remaining when again typically Dagnall pressed Chris Robertson and robbed possession to run through on goal but made a mess of his shot that he sliced well wide.
Orient held on though and to dig deep in stoppage time for three points and a seventh clean sheet in 10 appearances for Jakupovic.
Port Vale: Neal, Yates, Robertson, Dickinson, Loft, Myrie Williams (Hugill 84), Pope, Williamson, Griffith (Lines 61), Duffy, Birchall (Knott 61)
Subs not used: Johnson, Jones, Dodds, Grimmer, Hugill
Bookings: Duffy (65)
Orient: Jakupovic, Omozusi, Sawyer, Vincelot (Bartley 20), Cuthbert, Cox, James, Mooney (Batt 73), Odubajo, Clarke, Dagnall (Simpson 86)
Subs not used: Lisbie, Larkins, Lasimant, Ness
Goals: Cox (41) Clarke (57)
Bookings: Dagnall (35)
Referee: J Simpson
Attendance: 4,235 (224)