Glenavon gained revenge for Saturday's heavy defeat to Portadown by getting the better of their Mid-Ulster neighbours in the re-match at Shamrock Park.
Both sides had decent chances to go in front inside the opening half-an-hour. On 20 minutes Portadown's Lee Bonis fired wide inside the box but could only pull his effort wide while, a few minutes later at the other end, Gareth McCaffrey was denied by a combination of an acrobatic stop from Jacob Carney and a goalline clearance from Greg Hall.
But the deadlock was broken on 34 minutes when Glenavon substitute Andy Hall fired through a crowded box after Conor McCloskey had knocked on a loose ball from a corner.
Paul Finnegan might have levelled for the Ports a short time later with an ambitious attempt from the halfway line which keeper Craig Hyland was lucky to spill the wrong side of the post.
McCaffrey had another chance after that but was thwarted by the inrushing Sam Warde who slid the ball to safety, and there was a further opportunity for the visitors late in the half but McCloskey lifted his shot over from the edge of the box.
Glenavon moved further in front in the opening minute of the second half, a great solo effort from McCaffrey after he collected a throw in, brought the ball onto his left foot and fired past Carney into the bottom corner.
And they came close to extending their lead just after the hour courtesy of McCloskey's curling drive from the edge of the box but Carney was able to turn it around the upright.
Portadown pulled one back on 66 minutes through Chris Lavery after he poked the ball home from Adam Salley's cross into the six yard box.
The sides traded chances after that. Andy Hall sent a cross onto the bar moments later followed swiftly by a Conan Byrne effort which was deflected just over.
The Ports chased the equaliser with Salley cutting inside before seeing his low effort stopped by Hyland while Luke Wilson had a header cleared off the line by Aaron Harmon.