Central Coast scored a major upset over Sydney FC, winning 2-0 at home to inflict the first defeat on the reigning champions in nine months.
The match was supposed to be a routine 90 minutes for Graham Arnold's men, but the Mariners used pace and intensity to neutralise their opponets, with Andrew Hoole and Jake McGing scoring to seal the former Mariners coach's first loss at Central Coast Stadium since departing in 2013.
"We worked hard and the Mariners were red-hot tonight," Arnold said.
"You've got to give them credit."
Last campaign, it took 20 rounds for a team to defeat Sydney, when Western Sydney became the only side to down the would-be Invincibles in February's derby.
The Mariners managed it in six rounds, a result that propels Paul Okon's youthful team into an unlikely sixth spot for just the second time in two years.
From the outset, they prodded and poked holes in Sydney's rhythm -- or perhaps the champions did that to themselves, such was the disunity at times.
The hosts' near two-thirds of possession produced chances and it didn't take long for their counter-attacking streak to yield a fine team goal.
Danny De Silva set up the move after Luke Wilkshire turned over the ball on the left flank, trading passes with Connor Pain and Asdrubal.
Back in possession, the Spaniard anticipated the on-rushing Hoole and fed the former Sky Blue and Newcastle Jet who, after outrunning Michael Zullo, had only to maintain his composure to evade the wrong-footed Andrew Redmayne.
Sydney entered the break on the back foot but a stormy-faced Arnold knew his relentless squad's uncanny knack for a late fightback -- it had been 19 months since his side had conceded more than one goal and lost a match.
It became clear they might not make it to 20 after McGing headed in a Hoole corner, Josh Brillante guilty of losing sight of the ball.
That lit the fire in an already feisty affair, and Wilkshire earned a yellow for a tackle on Pain before bandaged-up skipper Alan Baro was given his marching orders six minutes from time after a second booking.