Wollongong United ended Bulli's 13-match unbeaten run and reignited the title race with a 2-1 win over the ladder leaders at Balls Paddock on Saturday.
The Reds' solid defensively display was rewarded with two second-half strikes which all-but secured their place in the finals and cut Bulli's lead at the top to just one point over Dapto Dandaloo.
Bulli remain on 46 points with the Fury in hot pursuit on 45 points while United are a further six points back.
To compound the loss for the Northern Suburbs club, keeper Bryce Daenell was dismissed in the final minute of normal time for denying a goal-scoring opportunity.
But it came after the Reds had already shot to a two-goal lead courtesy of Adrian Nikolovski and Scott Burleigh.
"They stood up and we grew a foot taller every time we attacked," United coach Oliver Vrtkovski said.
"I think that is why we got the goals late because we knew the longer the game went without conceding, we were going to score.
"We looked more dangerous in attack."
Before United scooted away for the win, both sides traded blows in the opening stanza of a tight contest, certainly indicative of two finals-bound squads.
It took a wonder strike from Nikolovski 10 minutes after half-time to finally get the scoreboard ticking.
The United man cut in from the right-hand side and fired a left foot effort from distance into the bottom corner.
Bulli's Guy Knight had a chance to equalise just past the hour mark but fired his one-on-one chance wide of the mark.
That proved costly as United doubled their advantage through Burleigh in the 83rd minute.
The defender was left inexplicably open from a corner to head home the visitors' second.
Ben McDonald headed in a consolation goal moments before the full-time whistle but it took nothing away from United's resilient performance.
"We weren't expecting much heading into the game, so we went in with a really simple game plan and it worked for us," Vrtkovski said.
"We had Mark Every out and Brendan Reilly and Robbie Shields hobbling on one leg but they knew the importance of the game for their teammates.
"We countered their play quite well.
"We both had our chances but I was quite comfortable with the result."
The win leaves United four points clear of South Coast United and five above Port Kembla with three rounds remaining after the Zebras defeated Fernhill 2-0 on Saturday.
At Ocean Park, Wollongong Olympic added to Woonona's woes in a 2-0 win and Albion Park White Eagles kept their finals' hopes alive by beating Bellambi 4-0 at Terry Reserve.