There was also the small matter of revenge at stake given that Ronnie McFall's side knocked the Glens out at the same stage last season on their way to famously lifting the trophy as a Championship side.

Unfortunately the occasion seemed bigger than the game with neither side able to get a grip on proceedings in the early exchanges until Waterworth struck on 20 minutes with what proved to be the only goal.

The 23-year-old frontman collected the ball some 40 yards from goal, brought it forward, beat defender Ross Redman and duly fired a low shot into the bottom corner from the edge of the area.

Glentoran thought they had doubled their advantage just four minutes later but Ciaran Martyn's 'goal' was ruled out after Waterworth was adjudged to have fouled Ports 'keeper David Miskelly earlier in the move.

Portadown might have gone in at the break on level terms, though, when Sean Mackle found himself clear with only Elliott Morris to beat but the 'keeper saved the day with his legs.

And they came close again just after the hour mark when Tim Mouncey squandered a great effort with the goal at his mercy while John Convery also tested Morris with a header from a Redman free-kick.

Despite this the Glens never really looked in any danger of surrendering their precious lead and now await the outcome of tonight's semi-final between Coleraine and Dungannon Swifts to learn their opponents in the March 27th final.