Curtis Allen's 73rd-minute goal earned Coleraine a draw in a lively Premiership clash at the Oval.
Former Bannsider Stephen Carson headed the Glens into the lead in the opening minute but Coleraine responded with Allen hitting the woodwork.
Elliott Morris denied David Scullion before the break as Coleraine continued to look the more dangerous side.
After Allen's equaliser, the impressive Gary Hamilton had a strong Glens penalty claim turned down late on.
It certainly appeared as though Howard Beverland had hauled back Hamilton deep in injury-time but the penalty appeals were turned down.
Hamilton's perfect delivery from a corner allowed unmarked Carson to nod the Glens ahead after only 45 seconds.
However despite the early blow, Coleraine fought back well and went on to carve out a series of chances which probably should have had them ahead by half-time.
Allen headed against the woodwork on 18 after outjumping Sean Ward and Morris then produced a great save to claw a Scullion headed off the line.
As Glentoran reasserted themselves, Carson went close with a deflected effort while Coleraine keeper Michael Doherty made a superb save to deny Ciaran Martyn.
But Coleraine dominated in the 20 minutes before half-time without getting on terms.
Scullion's cross only needed a touch to find the empty net but the ball flew across the face of goal.
Then youngster Ciaran Clarke missed another great chance but Morris reacted bravely to prevent the lively Leon Knight from finding the unmarked Scullion.
Morris again denied Allen before the break while Glentoran's first goal attempt in over 20 minutes came in first-half injury-time when substitute Martin Murray fired wide.
After the frenetic action of the opening period, there was something of a lull after the interval.
Hamilton and Ciaran Clarke missed half-chances at either end after the hour before Doherty kept Coleraine in the game with a brave save with his legs to deny former Bannsider Darren Boyce.
It proved an important save as Allen headed the equaliser on 73 after Johnny Taylor's sliced attempted clearance.
Andy Waterworth wasted a glorious chance to put Glentoran ahead by blasting wide after a heavy first touch.
Richard Clarke then came to Glentoran's rescue as he diverted Knight's cross out for a corner when Allen seemed certain to nod into an empty net.
But there was controversy right at the death as Hamilton had his penalty claim turned down.