Brisbane Roar's slick possession game made Farina's Sky Blues look embarrassingly second-rate on Saturday night after skipper Alessandro Del Piero succumbed to a calf injury.
Del Piero was due to have scans on Sunday but is unlikely to face Western Sydney Wanderers in what would be a deflating loss for an eagerly-anticipated local derby.
The Italian may not be the only change to Sydney FC as Farina blasted his side's poor attitude and a lack of fight after they conceded two set-piece goals in two minutes late in the first half.
The Roar exposed some of the Sky Blues' ageing legs but it was their lack of hunger which most upset Farina.
"It was like we didn't want to get into the fight and that's not something that I like,'' he said.
The former Socceroos coach indicated some players would pay the price for not maintaining the intensity required.
"One hundred per cent,'' he said. "At the end of the day, coaches are the ones that go in the end; players stay.
"I'll do everything I can to make sure this club is successful and if people aren't pulling their weight I'll change.
"Everyone is accountable. If we're not going well the team can change and will change.''
Brisbane ran riot after captain Matt Smith broke the deadlock in the 37th minute from a Thomas Broich free kick, and should have rattled up a more damning scoreline.
They looked like the Roar of old as they enjoyed twice as much possession and finished with 12 shots on goal to one.
And they did it without star striker Besart Berisha who was replaced after 25 minutes with a hamstring injury.
It was a victory to savour in front of 21,821 fans who also lapped up the commanding return of favourite son Matt McKay.
Former skipper McKay had a hand in two goals and was among the Roar's best, after rushing back from the Socceroos' midweek 3-0 win over Canada in London.
"He was keen to play and that shows the spirit amongst the players,'' said coach Mike Mulvey.
"The attitude of the players is absolutely fantastic.''
The only team with wins from their opening two matches, the Roar face a better test of their A-League credentials on Friday night away to Melbourne Victory.
