Sydney FC is trying to grow up; the benches at Moore Park this week were first world, all leather and steel, but Graham Arnold pulled a standalone plastic chair alongside to cheers from the fans behind – an ominous sign, if not an attempt at humour, that Sydney are not yet beyond their struggles.
Typical of matches involving Sydney FC this season, the first 10 minutes were nervous from both sides, though Sydney were more comfortable in possession, and were impressive in their passing – helped by a slick surface after a rainy morning.
It took Isaka Cernak to truly open the game up: played in behind Aaron Calver – deputising for the conspicuously absent Sebastian Ryall – with a raking diagonal pass from midfield which cleared the entire Sydney defence, though Janjetovic was quick to charge down the threat to make a solid save from Cernak's shot.
Sydney responded well, controlling the game through Mickael Tavares and the irresistable Milos Dimitrijevic, and went ahead on 15 minutes when Marc Janko rose unmarked at a corner to power a header past Matthew Nash in the Mariners' goal and put his side in front.
Almost immediately after the restart, the visitors looked to drag themselves level when Jacques Faty was caught out after letting a cross bounce past him, though Cernak failed to punish the mistake as Janjetovic threw himself in front of the midfielder's shot for a second time.
Despite increasing pressure from the Mariners, especially from out wide and on the counter, the 1-0 scoreline didn't seem particularly precarious, though perhaps a slightly relaxed Sydney side were only making it seem that way.
The visitors had another chance on the half hour when Ferreira slid a flat pass across the face of goal for a sliding Nick Fitzgerald to poke past the goalkeeper, but he arrived too late to the opportunity and only deflected it on and wide of the far post.
Suddenly the Mariners were coming into the game, and achieving more than the occasionally successful through pass lofted over Sydney's fullbacks.
With halftime approaching, they wrested back possession near halfway and split the Sydney defence before it could set itself to release Ferreira through the middle, who nutmegged Faty and lifted the ball over the onrushing Janjetovic.
It was, as the referee blew to end the half, no less than they deserved.
Sydney began the second half with a greater urgency than they did the first, and Janko should've given them the lead when he overpowered a free header almost directly in front of Nash's goal.
Five minutes later, Sydney were gifted another chance when the Mariners defenders let a cross run through to an unmarked Janko out the back, but his volley back across the goal was hit straight into Nash.
The game stretched from end to end, and the Mariners struck on the counter again: Cernak cut in from the left and drifted across the top of Sydney's 16 yard box before squeezing a pass to Fabio Ferreira who slammed the ball hard and low inside the far post to give the Mariners a 2-1 lead.
A draw at this point still seemed to be the fairer result, though the home side's complacency earlier in the match had left them open to a strong response from the Mariners.
1-0 up, and with a 5-1 win over the same opposition only a few weeks ago still fresh in the memory, Sydney made the mistake of sitting back and waiting for fate to do the heavy lifting.
With an unbeaten start to the year to maintain, Sydney picked themselves up and worked on reversing the shock.
It took 10 minutes, and a silly goal, before the scoreboard read 2-2: a ball was drilled in towards Janko on the penalty spot, and was held up and eventually rolled out for Rhyan Grant, who swung his foot across it and unleashed a drive from 25 metres that flew past Nash and nearly destroyed all logic within a 5km radius, drawing Sydney level with around 25 minutes left to play.
Sydney were looking more likely to win after their second goal, though the Central Coast remained dangerous on the break, as they had been all afternoon.
Ultimately, the home side's superiority shone through, and Shane Smeltz scored a truly skillful goal to put Sydney back in front. Picking the ball up from Janko inside the Mariners' penalty area, Smeltz chopped the ball outside once to take it away from the man sliding in, then cut inside to bring it onto his right before finishing low to Nash's right.
The Mariners had a chance to make it 3-3 in a moment of chaos late on, but Sydney's defence, shaky as it had been all afternoon, held firm as the crowd held its collective breath.
Minutes later, they were celebrating a fourth Sydney goal after Alex Gersbach pushed through on the left and squared a pass to Janko for a simple tap-in.
The final 4-2 scoreline seemed harsh on Phil Moss and the Mariners, though the result was probably right – Sydney had managed to score more goals, after all, and that's how football works.
Sydney ventures beyond Moore Park for the first time since February 6 next week when they travel across the city to face a resurgent Western Sydney Wanderers side.
The Mariners, meanwhile, will look to bounce back from this loss when they head to Newcastle; the two clubs still pushing Melbourne City and the Brisbane Roar for finals football.
Sydney FC starting XI: Janjetovic (GK), Calver, Faty, Petkovic, Gersbach, Tavares, Dimitrijevic, Antonis, Ibini, Brosque (C), Janko
Sydney FC substitutes: Necevski, Smeltz, Jurman, Naumoff, Grant
Central Coast Mariners starting XI: Reddy (GK), Roux, Anderson, J. Rose, Poscoliero, Montgomery (C), L. Rose, Caceres, Fitzgerald, Cernak, Ferreira
Central Coast Mariners substitutes: Nash, Hutchinson, Major, Trifiro, Kalik