Crawley Town gained their first home since January thanks to three first half goals from free-kicks.
In an extraordinary 11-minute spell, Reds scored three goals all from free-kicks by James Collins, Joe McNerney and Enzio Boldewijn.
The victory was Reds' first home win in seven matches, ending a miserable run at the Checkatrade Stadium.
Collins gave Reds the lead in the 23rd minute when he headed home a Josh Payne free-kick.
McNerney made it 2-0 in similar style, also nodding in a set-piece delivered by Payne.
As this wasn't enough Crawley went 3-0 ahead four minutes later when a long-range free-kick by Andre Blackman bounced and was flicked in over 'keeper Sam Sargeant's head off the post by Boldewijn.
Jimmy Smith volleyed a ball from a Lewis Young throw-in which was comfortably gathered by Sargeant.
Collins combined with substitute Billy Clifford to create a chance for Rhy Murphy which the keeper stopped.
Former Orient star Dean Cox came off the bench to replacing Boldewijn for the last ten minutes, giving him a chance to say goodbye to the visiting fans after he left the club hurriedly in September.
The second half was forgettable apart from a couple of chances by Boldewijn which went close plus others by Payne and Murphy as Reds ended up comfortably winners.
REDS: Morris, Young, Payne, Boldewijn (Cox 79), Smith (capt), Blackman (Lelan 72), Yorwerth, Collins, McNerney, Djalo (Clifford 57), Murphy
Unused subs: Mersin, Harrold, Bawling, Henderson
ORIENT: Seargeant, Kennedy, Kelly (capt), Parkes (Mezague 12), Massey, Atangana (Ochieng 81), Hunt, Semedo, Koroma (Liburd 61), Judd, Alzate
Unused subs: Grainger, Moncur, Clark, Abrahams
REFEREE: Trevor Kettle
ATTENDANCE: 2,918 (792 away)
MAN OF THE MATCH: James Collins.