Nicky Law struck a late penalty to ensure Exeter City picked up a 2-2 draw at St James Park.
The Grecians went ahead late in the first half through Pierce Sweeney's first goal of the season, before Lee Angol quickly brought Orient level just before the break.
Louis Dennis then saw his shot deflect off Aaron Martin and up in the net just after the restart, but Law calmly converted late on to continue City's unbeaten start to the league campaign.
Matt Taylor made no changes to the side that beat Carlisle United 3-1 at Brunton Park, as City looked to continue their positive run.
The Grecians started with great intent and Randell Williams carved out an opening of his own as he cut inside from the right and curled an effort on goal, which was subsequently dealt with by Dean Brill.
With a quarter-of-an-hour played, City came close once more when Williams found space on the right flank and crossed towards the back-post, however Pierce Sweeney was unable to direct his header on target.
Ryan Bowman was the first to really test Brill five minutes later, as Aaron Martin flicked on into the area. The centre forward smashed a half-volley, from a similar position to his goal against Mansfield Town, but this time the Orient goalkeeper’s torso got in the way.
City were persistent in their pressure and they nearly had an opener through Law who swivelled and shot into the bottom right-hand corner expertly, only for referee Peter Wright to deem his first touch as handball.
Sweeney was in amongst the action again as he retrieved the ball from a corner-kick to cross with venom, the ball came off of an Orient player and glanced the top of the crossbar forcing the ball out of play.
Only seconds later however, Williams headed the ball back towards the on-rushing Sweeney who drilled a low half-volley past Brill to give City the lead.
Despite the Grecians’ superior dominance, the O’s equalised just before half-time as Dale Gorman miscued a long range effort only for the ball to fall into Lee Angol’s path to tap home.
After a promising start to the second-half by City it was Orient’s Louis Dennis who got the goal in the 53rd minute as he cut in from the left and fired past Lewis Ward with help from a Martin deflection.
The Grecians continued to push for a goal and an eventful goalmouth scramble almost led to one, but Dean Moxey, Bowman nor Sweeney, who were all involved, could force the ball into the back of the net.
Alex Fisher, who came onto the pitch for Lee Martin, was millimetres away from connecting with another wicked Sweeney cross, however the visitors managed to clear.
With seven minutes of added time revealed from the fourth official, a sense of a comeback fell over St James Park, and that comeback came seconds later as Ben Seymour was fouled inside the penalty area. Law was the man to step up and he smashed in an equaliser to earn the Grecians a well deserved point.
Exeter City: Ward (GK), Sweeney, A. Martin (Parkes 75’), L. Martin (Fisher 68’), Law, Williams, Bowman, Moxey, Sparkes, Taylor (C), Collins (Seymour 90’).
Unused subs: Maxted (GK), Woodman, Jay, Richardson.
Leyton Orient: Brill (GK), Ling, Widdowson, Gorman (Clay 70’), Ekpiteta, Coulson (C), Maguire-Drew (Alabi 83’), Dennis (Wilkinson 75’), Angol, Marsh, Wright.
Unused subs: Sargeant (GK), Judd, Harold, Otis.
Yellow cards: Ling, Wright, Coulson, Maguire-Drew, Marsh, Clay.
Attendance: 4,933 (438).