A Leroy Millar header with only nine minutes on the clock got Larne off to the perfect start, and they continued to dominate possession, albeit lacking penetration in the final third in the early stages.
Although looking solid, Glenavon had little threat themselves, and the champions were comfortable in their 1-0 advantage at the break.
And if they lacked cutting edge in the opening 45, they certainly had their shooting boots on in the latter. Whatever Tiernan Lynch said at half-time worked wonders, as Larne hit two goals in two minutes.
The first, a classic striker's goal, was finished powerfully by Lee Bonis, while the second was converted by Andy Ryan.
Aaron Prendergast pulled one back three minutes from time, but Glenavon were long since consigned to the fate of defeat.
And quite fittingly, Larne weren't finished, responding almost instantly to hammer home a fourth courtesy of Paul O'Neill.
There was also a rip-roaring opening to proceedings in the meeting of Carrick Rangers and Crusaders, with the hosts awarded a penalty with a little over six minutes on the clock.
Crusaders' goalkeeper Johnny Tuffey denied David Cushley the opener however, saving the Carrick man's spot kick, and the away side took full advantage of their netminder's intervention.
A superb run and finish by Philip Lowry came right before the half-time whistle, with the lead at the break a little harsh on Carrick Rangers against the side five places above them in the Sports Direct Premiership table.
Often perceived as a dangerous lead, Crusaders looked rather at ease with their advantage, limiting Rangers to almost entirely shots from distance, as they held firm for the three points.
The 8pm kick off between Newry and Ballymena, the league's bottom two sides, was a rather uneventful clash, with a dour opening half seeing both teams cancel each other out to go in scoreless at the break.
Lewis Tennant was sent off with 23 minutes remaining, as Newry mounted pressure, but it was to no avail, with both sides sitting perilously adrift at the foot of the table.
Friday night's Sports Direct Premiership results:
Carrick Rangers 0-1 Crusaders
Larne 4-1 Glenavon
Newry City AFC 0-0 Ballymena United
