Institute went into a stunning lead with what is sure to go down as one of the quickest goals in recent memory, scoring after just 16 seconds.
Glentoran 2 - 1 Institute
The game had only just begun when Ryan Semple caught the Glens defence napping as he ran onto an Eamonn Seydak switched ball from the left to shoot past James Taylor.
Rocked by that setback, Glentoran dusted themselves off and piled the pressure on the visitors.
Hamilton sliced a shot wide from close range after four minutes, and after a fumble from Stute keeper Gavin Cullen, Colin Nixon saw his shot blocked.
Hamilton then struck the post with an overhead kick on 17 minutes as the Glens piled forward and the busy striker also fired just wide shortly after.
On 20 minutes Hamilton raced down the right, and looked to be held back by Ogilby, but the striker cut the ball back for Richard Clarke who somehow struck wide from 10 yards.
But two minutes later the equaliser arrived when Ruairi Boyle brought down Clarke and Hamilton stepped up to chip the penalty home.
There looked to be only one winner from then on but Stute were given a lifeline when Sean Ward fouled Joe McCready in the box for another penalty. But James Taylor, in for the axed Elliott Morris, saved Ogilby's weak effort.
Clarke forced a good save from Cullen with a wicked drive from 30 yards out on 35 minutes before a dramatic finish to the half.
Daryl Fordyce and McClean clashed off the ball, and after the Stute man raced towards the Glens midfielder they went head to head. Referee Simon Creaney sent both players off.
After the break most of the play was in the visitors' half but that allowed them to hit the Glens on the break and but for two great saves from Taylor - denying Kevin Ramsey and Shaun Holmes - the Drumahoe men could have been out of sight.
But on 72 minutes the Glens finally found the goal their dominance deserved when Clarke superbly lobbed Cullen from 22 yards to lift the tension from around the Oval.
GLENTORAN: James Taylor, Ward, Nixon, Leeman, Black, Gillespie (Martyn 87), Fordyce, Clarke, Hill (Fitzgerald 57), Hamilton, Halliday.
INSTITUTE: Cullen, Wray, Boyle, McClean, Ogilby, Seydak, Divin, Holmes, Semple (McClements 67), Ramsey (Lowry 61), McCready.
© UTV News