League One leaders Leyton Orient saw their unbeaten record disappear as Hartlepool hit them with their four-goal barrage.
Two strikes from Ian Moore with efforts from James Brown and Andy Monkhouse blitzed an Orient side, who had conceded just three goals in their first six league games.
Their efforts from John Melligan and Charlie Daniels proved to be no more than consolations.
The win was no more than Hartlepool deserved as the visitors were quick out of the blocks and dominated for long periods.Richie Humphreys saw a shot blocked by Orient defender Tamika Mkandawire and it came as no surprise when Hartlepool grabbed the lead on ten minutes.
Moore out-paced Alton Thelwell as he latched on to Richie Barker's through ball and, although keeper Stuart Nelson parried his first effort, the striker reacted quickly and fired home the rebound.
Hartlepool should have doubled their lead when Brown raced clear, but he dragged his shot wide.
Orient almost levelled on the stroke of half-time when Adam Boyd's right-wing cross found Wayne Gray but his header slipped wide.
After the break Hartlepool quickly added a second when Adam Chambers was caught in possession and the ball fell kindly for Brown to fire home from 22 yards as it bounced wickedly over an embarrassed Nelson.
Orient pulled a goal back with their first effort on target when Melligan rounded off a smart move with an effort from 25 yards that crashed in by the underside of the bar.
Orient's hopes of a comeback all but disappeared on 84 minutes when Monkhouse played a neat one-two with substitute Joel Porter before firing home.
Orient responded and Daniels netted his first goal for the club when he smashed home Melligan's cross from the right.
But the home side were caught pushing two many men forward when, deep in stoppage time, Moore grabbed his second of the game.