THE visitors grabbed the early advantage after a quarter-of-an-hour had elapsed when, in a somewhat scrappy finish, Ciaran Martyn met a Stephen Carson through ball before sending a shot in off a home defender.
Prior to that the Ports twice came close in quick succession when first Tim Mouncey headed narrowly over before Kevin Braniff had a goal bound effort well saved.
On 42 minutes Matthew Tipton might have levelled for Portadown only for his lob off Morris to come back off an upright.
Despite the Ports continuing to press after the break it took them until the 75th minute to finally draw level after he got a touch to a Keith O'Hara cross.
Then, right at the end of normal time, the Welsh striker secured the points for Ronnie McFall's side by getting on the end of a Brian Gartland header to turn a close range effort past Elliott Morris.
Portadown: Miskelly, Mackle, Redman, O'Hara, Ramsey, Tipton, Braniff, Mouncey, Tomelty, Gartland, McCafferty subs Murphy (not used), Lecky (replaced Mackle 71), Paget (not used), Clarke (not used), Burns (not used)
Glentoran: Morris, Johnston, Nixon, Ward, Howland, O'Hanlon, Callacher, Martyn, Carson, Murray, Beggs subs Clarke (replaced Carson 60), Waterworth (not used), Gibson (not used), McGovern (replaced Johnston 80), Boyce (replaced Beggs 46)
- Portadown's Matt Tipton celebrates his two goals at Shamrock Park (Picture: Stephen Hamilton/PressEye.com)