While the supporters were still taking their seats, the hosts went in front with just 77 seconds on the clock through Ciaran Martyn. He lifted the ball over Samuel Johnston after bursting on to Eoin Bradley’s flick-on.
For a long spell thereafter Glenavon dominated without really testing Johnston and they were punished on 20 minutes when the Welders equalised through a Danny McKee wonder goal.
A long ball down the right flank looked to be going out of play but McKee did well to keep it in, then tried a speculative lob from a tight angle and caught James Taylor off-guard as the ball floated over his head and under the bar.
And Rhys Marshall saved his blushes again just minutes later as Ethan Boylan rounded the goalkeeper, only for the defender to clear off the line.
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Bradley could have restored the lead for Gary Hamilton’s men on 26 minutes but his header from Guy Bates’ cross went over the bar from six yards.
As the second half got underway both sides had chances cleared off their respective lines. First Marshall came to the rescue again to the hosts, before Dan McMurray stopped a Bradley header from a Mark Patton corner.
The Welders’ steely resolve was finally melted on 69 minutes when Bradley put the ball around Johnston, Martyn stumbled over the ball buy Bates made sure from close range.
And two minutes later the game was put beyond doubt as Paddy McCourt linked up with Martyn. Andy Hall was the lucky recipient and made no mistake with his well-struck effort.
Those of a nervous disposition had to look away when McKee made it 3-2 from the penalty spot on 87 minutes, but a minute later Bates bagged his second, tapping in a Patton cross at the back post.
GLENAVON: Tayor, Kilmartin, Marshall, Bradley, Hall, Patton, Doyle, McGrory, McCourt, Martyn, Bates. Subs: Hamilton (Bradley 76), Neill (McCourt 75), Marron, Braniff, Singleton (Kilmartin 73).
HW WELDERS: Johnston, Devine, Armstrong, Harris, McMurray, Dickson, Deans, Bowers, McKee, Boylan, Middleton. Subs: Shields, S Dornan (Boylan 80), Whittle (Dickson 89), C Dornan (Bowers 89), McConnell.
REFEREE: Keith Kennedy (Lisburn