The Lilywhites raced into a 3-0 lead on a heavy pitch at Deepdale, the victory their second in a row after beating Chelsea the week before.
Orient’s Tommy Taylor headed into his own net to hand North End the lead, with Steve Doyle and Paul McGee then on target.
The second half was in the main about Nobby Stiles’ men sitting on their lead and blunting the visitors’ attack.
Their job was made more straight forward when Orient had Stan Bowles was sent-off for his second act of dissent towards referee George Tyson.
PNE boss Stiles reverted to a 4-3-3 formation for the visit of the O’s, having played 3-4-3 when beating Chelsea the game before.
Gordon Coleman moved to left-back from midfield to track Orient winger John Chiedozie.
An early chance fell to Orient striker Ian Moores but he was denied by PNE keeper Peter Litchfield.
He had kept his place after a man of the match display on his debut against Chelsea.
North End went in front in the 11th minute, McGee getting the ball down the right hand side of the box.
With the angle too narrow for a shot, McGee chipped a cross into the middle in a bid to find Alex Bruce.
Taylor tried to stop the ball from reaching Bruce but succeeded only in putting the ball into his own net.
Soon after the goal, Bowles was booked for dissent.
The second goal came in the 25th minute, Mick Baxter and Graham Bell linking-up to work the ball into the box.
Doyle met it and rifled a shot into the net for his first goal of the season.
Ten minutes before the interval PNE netted their third goal. A long clearance from Litchfield was knocked on by Bruce into the path of McGee who slotted home.
It was McGee who ended up with the man of the match award for an all-action display in the attack.
In the second half it was Orient who did most of the attacking as they sought to claw a way back.
North End seemed to tire on a muddy pitch and playing against a strong wind.
Litchfield made a couple of saves from Moores before Orient went down to 10 men when Bowles again spoke out of turn to Mr Tyson and was given his marching orders.
McGee was denied by a good tackle from Nigel Gray in the box as he shaped to shoot, while at the other end Joe Mayo, Peter Taylor and Billy Jennings had chances.
Victory lifted PNE to fifth from bottom of the Second Division. But they lost their next four matches to fall right back into trouble.
They rallied with two wins and two draws but a 3-1 defeat at home to Swansea left safety out of their own hands going into the final game at Derby.
North End won 2-1 at the Baseball Ground but Cardiff stayed up at their expense by getting a draw with champions West Ham.
PNE: Litchfield, Westwell, Baxter, Anderson, Coleman, Doyle Burns, Bell, Naughton, Bruce, McGee. Sub (not used): Elliott.
Thanks for reading. If you value what we do and are able to support us, a digital subscription is just £1 per month for the first two months. Try us today by clicking here