Brisbane were beaten 2-0 by second-placed Sydney in their final match of the regular season at Moreton Daily Stadium on Saturday.
Goals from Kosta Barbarouses and Harry Van der Saag opened the door for the Mariners to move above the Roar and take third place, an opportunity they grabbed with both hands.
Jack Clisby struck in the first half and Marco Urena sealed the victory in stoppage time at Central Coast Stadium.
Alen Stajcic will pit his wits against fellow former Matildas coach Ante Milicic in an all-New South Wales clash next Saturday.
The Roar will have an extra day to prepare for a home showdown with Adelaide United a week on Sunday, when a place in the semi-finals will be up for grabs.
Newcastle Jets moved off the bottom of the table courtesy of a 1-1 draw with Perth Glory, A Jonathan Aspropotamitis own goal giving them a point after Bruno Fornaroli opened the scoring.
That point moved the Jets above Melbourne Victory, while Perth remain ninth.
Western Sydney Wanderers will host Macarthur FC in the 2020-21 season opener on December 27, it was revealed on Tuesday.
The other opening games will see Western United host Adelaide United, Wellington Phoenix visit Brisbane Roar, Sydney FC take on Melbourne City and the F3 Derby between Central Coast Mariners and Newcastle Jets.
The opening round would seem like just another game, but history shows otherwise.
With the help of Opta data, we assess just what round one means in the A-League.
Opening loss and trophies become difficult
Incredibly, only twice in A-League history has a team that lost in round one gone on to be crowned champions or premiers of that season.
The first instance came in 2011-12, when the Mariners were edged by Brisbane in round one, but went on to win the Premiers' Plate, finishing two points clear of the Roar.
Melbourne Victory were the second, going on to be crowned champions in 2017-18 despite a 1-0 loss to Sydney FC in round one.
In all, six of the nine teams to do the A-League double of being crowned premiers and champions in a single season have done so far after winning in round one. The other three drew. Of the 15 champions, seven have won and seven have drawn, to go with Victory's 2017-18 defeat, in round one. Nine of the 15 premiers have won in the first round, alongside five draws and the Mariners' loss.
Round one looks hugely important in the A-League.
Fast-starting Sydney, Glory woes
Sydney have scored more goals (21) in round one games than any other team in the competition, while earning the most points per game (1.7) of teams to have featured in at least five seasons.
The Sky Blues have lost just two round one matches in their history, and the most recent of those was in 2012-13. They face a huge test to begin 2020-21 season, hosting Melbourne City in a Grand Final rematch at ANZ Stadium.
On the other hand, Perth Glory have lost more games in round one than any other team in A-League history with seven.
In contrast to Sydney, Perth are winless in their past five openers, their last win coming in 2014-15.
The 2019-20 A-League campaign has been suspended since March due to the COVID-19 crisis, but Australia's premier football competition is set to restart on July 16 followed by a five-game finals series – the Grand Final to take place on August 23.
A derby between Melbourne Victory and Western United – originally scheduled for AAMI Park in Melbourne – will be played at a stadium still to be determined due to a spike in coronavirus cases in the state.
Six venues will be used in New South Wales and Queensland with the potential for more to be added subject to government regulations – ANZ Stadium (NSW), Bankwest Stadium (NSW), Central Coast Stadium (NSW), McDonald Jones Stadium (NSW), Jubilee Stadium (NSW) and Cbus Stadium (QLD).
"Over the past three months all stakeholders have been working hard together with one goal in mind – To finish what we started," FFA's Head of Leagues Greg O'Rourke said on Wednesday.
"We know the COVID-19 environment has been very difficult for many people in our community and we hope that delivering an extravaganza of matches will allow our fans to basically see a game everyday will be a unique experience for those who have stood by us.
"As we are a truly national game, the current border controls means that some of the match day venues may need to change, however we have secured venues in both a NSW Hub model and a hybrid hub model which has most games in NSW but allows for a few games in other states.
"Whilst we don't see the draw changing, the planning we have undertaken provides us with agility to shift between certain states if required. This version of the draw displays our current venue plan.
"We will continue to work with the Federal and State governments to ensure the health and safety of our players, coaches and other stakeholders and have detailed and practical protocols in place for all parties involved in training and match days.
"I am excited to see us kick off the restart and ultimately finish off what we started last October, with our priority always being to be in a position to crown our Hyundai A-League premiers and champions for this season."
Defending champions Sydney FC top the table by eight points through 20 matches, though second-placed Melbourne City have played three games less.
Last week, the PFA threatened to initiate legal proceedings against Perth Glory owner Tony Sage following his decision to stand down players, with the A-League season on hiatus due to COVID-19.
The Mariners also issued stand-down notices as the league's postponement impacts clubs financially, prompting the PFA to serve Central Coast owner Mike Charlesworth with a letter of demand.
"These actions undermine attempts for our game to overcome common challenges, fight for common interests and re-establish our sport," PFA chief executive John Didulica said in a statement on Tuesday.
"While other codes have fostered unity and demonstrated leadership amid crisis, we are at risk of regressing to the lowest common denominator.
"FFA has indicated an intention to intervene as this matter escalates.
"This morning, we have written to FFA to ask they follow the lead of other sporting codes in this country and lead a collective and uniform solution to our common challenge."
Football Federation Australia (FFA) has already stood down approximately 70 per cent of its staff in a bid to save money amid the coronavirus crisis.
Coronavirus has claimed more than 37,500 lives globally, with over 781,800 confirmed cases.
In Australia, there have been at least 18 deaths and more than 4,350 cases.
In a statement on Saturday, the PFA threatened to initiate legal proceedings against Glory owner Tony Sage.
The PFA said it had "been provided with stand-down notices issued to its members at Perth Glory" by Sage.
"The players acknowledge that everybody in Australia is facing a collective challenge as a result of the COVID-19 pandemic," PFA chief executive John Didulica said.
"In times like this, our community needs leadership and, from the perspective of football, a commitment to collaboratively rebuilding our sport.
"The PFA continues to call for a collective solution to address our game's challenges, as has been the approach adopted by the AFL and sporting bodies around the world. However, Tony has shown his preference for unilateral, reckless and unlawful action.
"A fortnight ago, it was fine to relocate players to the east coast away from their families and expose them to a global pandemic. Now, when the opportunity arises, it is considered acceptable to stop paying them. These are not the traits of a sport that values its people.
"We are positioned to take the same course of action if any other A-League club owner elects to take this course of action in contravention of both the law and the sports broader needs at this time."
Perth Glory decided against commenting when contacted by Stats Perform.
Interim coach Grant Brebner named four teenagers in his starting XI for the clash at Sydney's Netstrata Jubilee Stadium as Victory ended an unwanted club record four straight defeats.
They had to be patient as Perth controlled most of the early possession but Rojas leathered in a 25-yard effort into the top-right corner to get them up and running.
Tarek Elrich dragged down Andrew Nabbout on the hour, with the winger converting the penalty he won, before Rojas' composed finish – his fourth goal in two games – meant it was game over.
Elvis Kamsoba scored his first A-League goal in injury time to complete proceedings, as Victory – who are guaranteed to finish 10th with just one game to play – returned to winning ways.
Glory's third loss in five since the season resumed means their spot in the top six is still not officially locked in, although their Finals place will be confirmed if Adelaide United do not beat Melbourne City on Tuesday.
