On a heavy pitch soaked from overnight rain, Hengrove had the first chance but Jamie Powell saved well from Jack Fillingham's header. His opposite number in the Athletic goal, Mark Drinkwater, then had to save from former Hengrove attacker Paul Coles.
Hengrove had the ball in the net just before half time through Asa White but the "goal" was disallowed for offside; the O's then took the lead eight minutes into the second half when Ryan Ashwood finished from close range.
Hengrove sub James Dunn scored with his first touch after coming on in the 59th minute and Powell reacted smartly to deny Dunn again a minute later as he looked for a second. With ten minutes to go, ref Alastair Francis awarded a penalty to the visitors when Elliott Saunders was fouled in the box and Saunders took it himself, sending keeper Powell the wrong way.
Oldland then hit back when Jason Side equalised with just four minutes to go to rescue a point for the O's, his second goal in two home games recently.