It the third league win on the bounce for the Phoenix and its significance is crucial.
It was also just the second loss across 14 games in all competitions this season for the Victory and their only other defeat (against Perth) came in a match where they were reduced to 10 men for a long period.
Melbourne fans may point to an FFA Cup hangover, after they lifted the knockout trophy on Saturday, but they were also fresher than their opponents, with an extra day ahead of the match.
It was a composed and confident performance from the Phoenix and showed what is possible when they have most of their big guns on the park.
They dominated possession (58 per cent) and generally looked more dangerous in the final third.
Goalkeeper Oli Sail was a standout, while new English import Scott Wootton made his first start and was a vocal presence, marshalling the back four well alongside Josh Laws.
David Ball was dominant up front – with some classy touches - while Piscopo and Gael Sandoval found space in central areas, with the Mexican in particular making the most of a roving commission. Fullbacks Sam Sutton and Tim Payne got forward well on the flanks.
After being bottom of the table heading into last weekend, the Phoenix are now seventh and have a great platform to build on.
Like all Tony Popovic-coached teams, the Victory are built on a defensive platform and their ability to reset immediately in transition made them tough to break down.
The first half was a frenetic affair. There was an impressive tempo, with the Phoenix exhibiting some of their best work in possession this season.
The home side dodged a bullet in the 24th minute, with Sail making a strong block of a Chris Ikonomidis effort, with the rebound spinning away from danger.
Ball exhibited some silky skills to get clear – before a late block – and the English striker also went close with a near post flick from a corner.
Between them the sides managed seventeen shots in the first half, though most from long range, with only one each on target.
Sail denied Gbenga Folami with a superb save just after the hour, with All White Marco Rojas coming on soon afterwards for his 100th match in navy blue.
Rojas should have scored in the 69th minute, but he directed his shot just wide of the post, after exhibiting wonderful technique to gather in a Jason Davidson cross.
The deadlock was finally broken in the 74th minute, after some excellent work from Ball. The 32-year-old swooped on an errant pass from Davidson, drew two defenders before laying off to Piscopo, who swept home with aplomb from 12 yards.
Just like in the FFA Cup semifinal, the Victory brought some heavy artillery off the bench but couldn't make an impression, with Wellington defending their lead expertly to clinch a vital win.
Wellington Phoenix 1 (Reno Piscopo 74')
Melbourne Victory 0
