Goals from Jamie Tomelty and Peter Thompson gave the Blues victory in the Irish Cup semi-final at Windsor Park.
Andrew Waterworth struck a post for the Glens before Tomelty blasted into the top corner for a 32nd minute opener.
Glentoran wasted a series of chances with Matty Burrows denied by a fine Alan Blayney save.
Thompson made it 2-0 on the hour with a superb turn and shot past Elliott Morris.
An early flurry of chances saw Glentoran's Johnny Taylor head over and Tomelty wasted a backpost chance before Waterworth's 20-yard shot hit the woodwork.
Tomelty made amends when he rifled into the net from Mark McAllister's lay-off.
Blues full-back Jim Ervin was perfectly placed to clear after keeper Alan Blayney failed to hold Grant Gardiner's shot.
Blayney was nearly punished just before the break when he failed to claim the ball from a corner but Jimmy Callacher could only head wide.
The keeper showed his class early in the second half by racing out and smothering a Burrows strike.
Callacher squandered another excellent opening before Thompson gave the Glens a lesson in finishing.
The striker swivelled 20 yards out and delivered a crisp shot beyond the outstretched Morris and into the corner of the net.
Blayney made another superb save from Burrows while Morris tipped over a Curtis Allen effort in the closing minutes.
Thompson was delighted to make the final as he clocked up his 27th goal in 28 Irish Cup games.
"It wasn't going to be a day for pretty football but at times we played some good stuff," he said.
"The important thing in semi-finals is getting through to the final and we have done that.
"The Irish Cup has been good to me although I've been fortunate to play in a team which creates plenty of chances."