Central Coast's lead at the top of the A-League table has been cut to one point after suffering a shock 2-1 loss to strugglers Perth Glory on Saturday night.
The Mariners were on track for victory after Bernie Ibini's 13th-minute strike at nib Stadium.
But goals either side of half-time to Travis Dodd and Shane Smeltz secured all three points for the Glory, who remain four points adrift of the top-six ahead of next week's away clash with Western Sydney.
Central Coast (42 points) have lost just three times this season and are still in a good position to take out the minor premiership.
But with Western Sydney (41) showing no signs of slowing down, the Mariners have a fight on their hands to retain top spot.
The next fortnight will prove crucial for Central Coast, who take on Melbourne Victory and then Western Sydney in games at Bluetongue Stadium.
For Perth Glory, it was a sweet end to a week that started with the sacking of coach Ian Ferguson.
A five-game losing run proved to be Ferguson's downfall, with interim coach Alistair Edwards enjoying a winning start to his tenure at the helm.
An ecstatic Edwards gave a double fist pump to the crowd when the final whistle was blown.
Perth still have plenty of work to do over the final six rounds if they are to make the finals.
But last season's grand finalists will take a massive confidence-boost from their win over the Mariners.
Central Coast striker Daniel McBreen was the architect behind the opening goal, stripping Steve McGarry of the ball in defence to give Ibini a one-on-one chance against Glory goalkeeper Danny Vukovic.
Despite having a Glory defender right on his tail, Ibini made no mistake with the finish, firing a smooth strike past Vukovic to give the visitors the early edge.
Glory fans started becoming increasingly frustrated with some of their team's slow build-ups from defence.
But the slow-and-steady approach paid dividends in the 27th minute, with a pin-point long ball from Nick Ward finding a small gap in Central Coast's defence.
A running Dodd put the finishing touch on the move, expertly trapping Ward's pass with his right foot before firing a beautiful shot with his left.
Smeltz then sent the 5909 crowd into raptures in the 64th minute when his powerful header hit the back of the net, with Mariners goalkeeper Mathew Ryan unable to keep the ball out despite getting a hand to it.
"I couldn't be prouder of the players," Edwards said.
"It was really pleasing to not only get the three points, but to put on a good performance. We controlled the game for large parts, particularly in the second half."
Mariners coach Graham Arnold was scathing of his team's performance.
"It was probably the worst performance since I've been at the club," Arnold said.
"We were totally out-enthused and we were second to everything.
"We were definitely second best."
Who will win this year's Champions League?