Yeovil were made to pay for Paul Wotton's penalty miss as Leyton Orient battled from behind to claim a point.
The O's went ahead through David Mooney's close-range header before Kieran Agard levelled after following up Ed Upson's free-kick.
The Glovers went ahead when Bondz N'Gala headed home an Upson corner.
Wotton fired his spot-kick wide after a Scott Cuthbert handball and Mooney equalised from the spot after he was fouled by home keeper Marek Stech.
VIEWS FROM THE DRESSING ROOM
Yeovil Town manager Terry Skiverton told BBC Somerset:
"In the first half some of our play was scintillating and I thought we carved them open time and time again.
"We got ourselves into a decent position and if we'd put the penalty away the game would be put to bed.
"But it gave them that bit of a lifeline... they'll be the happier out the two of us."