The Kings might have lost 11 of their last 13 games coming into Friday's home clash against the Townsville Crocs, but Shane Heal's men found a way to win 81-74 and that has now locked Sydney into play in the finals for the first time since the 2007-08 season.
Sydney finished with a 27-3 record that season before losing the grand final to the Melbourne Tigers, and then thanks to disgraced owner Tim Johnston's troubles the club folded before being brought back ahead of the 2010-11 season.
After finishing ninth and seventh the previous two seasons, the Kings will now likely finish in fourth position and a semi-final berth against the two-time defending champion New Zealand Breakers.
Sydney's place in the finals was secured on Friday night when the Melbourne Tigers travelled to Cairns, and beat the Taipans 66-64 in a heart stopper. Both teams were still a chance to make the finals going into the game, but now just Melbourne stays alive.
That means that New Zealand, Perth and Sydney are guaranteed of playing finals with the first semi-final matches to be played next Thursday. The fourth and final team will either be the Wollongong Hawks or the Melbourne Tigers.
The Hawks can guarantee their spot with a win at home over the wooden spooners Adelaide on Saturday night, or the Tigers can book their spot with a win on Sunday over Townsville if Wollongong loses the day before.
Sydney was spearheaded by a dominant performance from import Darnell Lazare (21 points, 4 rebounds) and some last-quarter heroics from Aaron Bruce (16 points, 6 assists to beat the Crocs.
"Different guys stepped up tonight and there was a lot of character in the team - that was the most pleasing thing," said Kings coach Heal.
"I'm really pleased with their effort today."
Only Olympian Peter Crawford (21 points, 5/12 three-pointers) consistently found his range for the visitors, while centre Luke Nevill (19 points, 6 rebounds) was a force inside.
"I think the effort level was far superior to the last time we played Sydney, but you've got to give credit where credit's due and Sydney got the job done down the stretch," Townsville coach Paul Woolpert said.
It was a tight affair right until the final whistle.
With 33 seconds left on the clock and the Kings leading by a slender two points, a monster three-pointer from Bruce gave Sydney the five-point advantage they needed to finally shake off the Crocs.
Townsville had looked like they might put themselves into the finals equation, holding a 10-point lead early and going on scoring runs throughout, but they were unable to find consistency across all four quarters.
Melbourne kept their NBL finals dream alive and crushed Cairns' hopes with a thrilling 66-64 away win.
The game was in the balance in the final quarter, with red-hot Chris Goulding (25 points) making the crucial basket.
He got his chance after a cruel offensive foul on Alex Loughton was called just as the Taipans were mounting a play to win the game.
With star Jonny Flynn injured on the sidelines, Goulding was outstanding for the Tigers, continually blowing past the Cairns defence to the hoop.
Their efforts on the boards were also crucial, leading offensive boards 14-3 at the final break.
While Goulding was able to silence the 5000 devoted home fans with that skill, it looked like Cairns may slide away victorious despite his heroics.
Cam Tragardh (11 points) and Shane Edwards (15 points) gave Cairns a bright start, two massive jams from Edwards the highlight of an otherwise grinding first half.
Starting the final term down two, Cairns pushed ahead thanks to triples from Loughton (15 points) and Aaron Grabau.
When Grabau dived for a crucial loose-ball get, the noise levels increased and it looked like the Taipans would ride it home.
But Goulding capped off a night of brilliant one-on-one moves with yet another drive to the basket the Cairns' defence had no answer for, and the Melbourne's defence held firm on the final play.
Friday night's other game saw the first-place Breakers travel to Perth to face the second-place Wildcats, but it counted for nothing with their spots in the playoffs secured.
The Wildcats prevailed, though, 73-58 to record a 13th straight win inside the Perth Arena and also end New Zealand's 16-game winning run.
Kevin Lisch top-scored for the Wildcats with 24 points while Shawn Redhage added 14, Jesse Wagstaff 13, Matt Knight 12 (and 13 rebounds) and Rhys Carter 10 (and six assists, five rebounds and two steals).
Wildcats coach Rob Beveridge felt it was ideal preparation for the finals that start next week.
"I don't know if it's a psychological advantage but we know we can beat anybody in this league, simple as that. We know we can win in New Zealand and obviously we wanted that first place, but it didn’t happen," Beveridge said.
"Right now it's about us taking care of the playoffs and anything can happen. It's a new season now and we have no idea who we are playing, but right now we feel pretty good about the way we are playing."
Corey Webster continued his breakout season for New Zealand with 18 points while Mika Vukona had 11 points and 13 boards for the Breakers. Alex Pledger also had nine points and seven boards, and CJ Bruton eight points.
Breakers coach Andrej Lemanis has quickly turned his attention to Thursday's semi-final Game 1, but it's hard to fully prepare when it still could be either Sydney, Wollongong or Melbourne that his team plays.
"The most important thing for us right now is getting ready for Thursday. One of the things we are certainly aware of is that everyone is talking about us and Perth being in the grand final, but it's 0-0 now," Lemanis said.
"Everything is wiped clean and it's the first team to win two games. It doesn’t matter what you have done through the season right now.
"We have to get ready for Thursday and Perth is the furthest thing from our mind right now. It's all about who we are going to play and we still don’t know who that is."