Wellington extracted sweet revenge for their fourth round defeat by Melbourne Victory with a 5-0 win at Westpac Stadium.
Outplayed and defeated 3-2 at AAMI Park in November, the Phoenix returned the favour is spades over third-placed Melbourne, in the process extending their unbeaten run to five games.
It was just their second home victory of the A-League season, and closes them to within two points of sixth place and the playoffs after going without a win for the first 10 games.
The battle for midfield dominance was intense right from the first whistle, and Welllington were the first to break through in the 18th minute when Vince Lia slipped a tantalising pass through to the edge of the box.
Young striker Tyler Boyd, who earned a start at the expense of the out-of-touch Jeremy Brockie, let the ball run and Hernandez slotted home under the diving Nathan Coe to put the Phoenix in front.
Melbourne looked disorganised in the front third on the rare occasions they found themselves on attack, and a succession of miskicks and skied shots were all they had to show as halftime neared.
But just as it look like the Phoenix's would take a 1-0 lead into the break, Kenny Cunningham took one touch 20m out and unleashed a perfectly placed dipping strike to double the lead.
And barely a minute later, Rashid Mahazi's challenge on Hernandez in the box had referee Adam Kersey pointing to the spot for the Costa Rican to calmly convert into a 3-0 halftime lead.
Melbourne showed more intent in the second half but, urged on by a vocal 6813-strong crowd, the Phoenix continued to press hard as they restricted the Victory to only the rare foray on goal.
The icing on the cake came in the 86th minute when Brockie, goalless since scoring in round four against the Victory, came on and slammed home a class Albert Reira through ball for the Phoenix's fourth.
Barely two minutes later, Sein Huysegems rounded off an outstanding night with his seventh goal of the season.
Then, a Mile Sterjovski rocket has ensured Sydney FC endured their fifth consecutive winless week, with the Central Coast Mariners downing the Sky Blues 1-0 at Allianz Stadium.
Sterjovski's 58th minute strike was enough to ensure the three points, lifting the defending champions to third on the ladder while Sydney sit in seventh.
Both teams came out on the attack firing a handful of strikes in the opening stages.
Nicky Carle, back from suspension, got things started when he went for goal in the first minute but shot wide.
The Mariners returned fire moments later with Storm Roux threatening before a Daniel McBreen strike was saved off the line by Sydney's Corey Gameiro, who chested it to safety.
Several golden chances were to follow for the Mariners with Josh Rose, Matt Simon and Nick Fitzgerald finding themselves one-on-one with Sydney keeper Vedran Janjetovic.
Rose made a bustling run down the left and drew a great save form the gloveman.
Simon could also have put the visitors ahead but headed wide before Fitzgerald caught Janjetovic off his line, but the keeper needn't have scrambled back with the shot going wide.
Ranko Despotovic had the 16,006-strong crowd on their feet when he looked to have broken the deadlock in the 30th minute but was ruled offside.
Alessandro Del Piero, Gameiro, Pedj Bojic all got in on the action with shots of their own but Ali Abbas had Sydney's best chance of the half forcing a save from Liam Reddy just before the break.
Gameiro could have put Sydney in front early in the second stanza.
But it was the visitors who opened the account in the 58th minute with Sterjovski's long-range missile, copping a deflection off Sydney's Matthew Jurman on the way and finding the back of the net.
McBreen and substitute Bernie Ibini kept Janjetovic on his toes while Sydney coach Frank Farina brought on returning striker Joel Chianese and handed new recruit Milos Dimitrijevic his debut in an effort to add fire power up font.
But in the end Sterjovski's strike was enough to ensure the result.