Randwick-Petersham has come back from the dead to claim its first Limited-Overs Cup title in nine years, beating Sydney by eight runs in a thrilling grand final at Drummoyne Oval.
Sydney looked to have the game well in hand when it reached 1-118 in response to the Randy Petes' 9-232, but lost their next nine wickets for just 105 runs to miss out on a second crown in three seasons.
Veteran Randwick-Petersham wicket-keeper Anthony Sams was awarded the Michael Bevan Medal for player-of-the-match after making an invaluable 44 and backing it up with five catches and a stumping behind the stumps.
"A lot of people were writing us off but I always knew what this side was capable of," winning captain Jason Sangha said.
"I am very proud of each and every player. We fought right to the end."
Disappointed Sydney skipper Matt Rodgers offered no excuses for his side's dramatic collapse.
He said: "We knew they would play right to the end and execute well in everything they did.
"Congratulations to them. It was a great game of cricket and they got it right at the end."
Randwick-Petersham won the toss and batted first but their total looked a little underdone despite decent contributions from Sams, Tim Affleck (39) and Adam Semple (44 not out).
Sydney quick Harry Manenti (3-49) mopped up the tail with a hat-trick in the final over, almost going on to claim a rare double hat-trick.
His side's openers Justin Mosca (41) and Ryan Felsch (68) wasted little time getting on with the run chase, putting on 87 for the first wicket in super quick time.
But their departures gave the visitors renewed hope they could turn the game around.
Caelan Maladay (2-8), Riley Ayre (2-32) and Jason Ralston (3-40) stepped up to the mark, ripping through Sydney's top and middle order.
The Tigers at one stage lost 4-16.
Ben Manenti (48) was proving the one stumbling block, working with the tail in a bid to drag his team over the line.
Sydney headed into the final over needing 13 to win, but it was all over when Manenti top-edged a catch on the third ball.
Randwick-Petersham's raucous band of supporters engulfed the victorious players after the final delivery, kick-starting a long night of celebrations in Sydney's east.