They defended well for long spells and won the game with a scrambled late goal.
The first half did little to warm up the fans as neither team showed many attacking ideas in what should have been near-perfect conditions.
Hartlepool's Andy Monkhouse dragged a low shot well wide of the Orient goal, and Scott McGleish did exactly the same at the other end as the visitors broke out from defence.
Top scorer Joel Porter curled a chip over the Orient bar from the edge of the area and it wasn't until the half hour that either keeper was called on to make a save, Orient's Jamie Jones tipping a curling volley from Lewis Guy wide on the right over his own bar.
The second half didn't get off to much of a start, either, though the O's' Jimmy Smith tried to inject some life into the game when he got on the end of a weak home clearance and sent in a low shot from 25 yards that was deflected wide of the home goal by a defender.
That heralded a spell of chances for both teams, Orient keeper Jones doing well to tip a shot from home sub Liam Henderson over the bar and then saving a Monkhouse header under his own bar.
At the other end, home keeper Arran Lee-Barrett did well to tip a shot from Adam Chambers round his right-hand post.
The winner came ten minutes from the end when Charlie Daniels floated in a free-kick and, after McGleish;s header, Gary Liddle's attempted clearance hit Tamika Mkandawire on the chest and rebounded into the roof of the net for a dramatic winner.