Geylang International sensationally sent defending champions Brunei DPMM tumbling out of the TNP League Cup after claiming a shock 4-2 win at the Jalan Besar Stadium on Thursday night.
Bruno Castanheira was the hero on the night as he scored three of Geylang's four goals to send them through to the final four at the expense of the wasps.
This was the Eagles' first-ever win against DPMM in 12 competitive matches and also marked their 12th win in 16 games over the past two years on the artificial turf of Jalan Besar.
Despite dominating the early proceedings, DPMM was unable to trouble Yazid Yasin in the Geylang goal. Instead it was the Eagles who managed to break the deadlock on 15 minutes.
The DPMM players seemingly stopped play after Hafiz Osman went down with a head injury, allowing Tatsuro Inui to break free into the attacking third.
The latter squared the ball across for Castanheira, who took one touch to steady himself before unleashing a 20-yard curling shot beyond the outstretched arm of Wardun Yussof.
They doubled the advantage seven minutes later through another swift counter-attacking move.
Inui played the role of provider again as he slipped a through ball in behind the DPMM defence which caused a mix-up between Boris Raspudic and Wardun, allowing captain Jozef Kaplan to slot home into an empty net.
However credit to the Bruneians, they managed to level things up before the break, with both goals coming from set plays.
First it was Paulo Sergio who whipped home a neat 25-yard free kick beyond a rooted Yazid on 30 minutes.
Eight minutes later, strike partner Ramazotti got to the end of Najib Tarif's free kick and flicked his resulting header inside the left-hand post.
The Wasps continued to dominate the game after the restart but was unable to turn their possession into goals.
Instead it was Geylang who went down the other end and managed to score another two in quick succession to seal three points.
Firstly on 69 minutes, Kaplan released Castanheira through on goal and the latter slotted a neat finish beyond the onrushing Wardun.
Two minutes later, the same combination worked to devastating effect. After Brian McLean saw his header from Najib's corner coming back off the bar, Kaplan went on the counter and clipped a superb ball for Castanheira to finish clinically past the DPMM custodian for his hat trick.
DPMM coach Steve Kean reacted by putting Awangku Fakharazzi and Shahrazen Said on thereafter, but there was no way back for the holders with Ramazotti heading wide twice late on.
Eventually it was Geylang who picked up the three points to see them top Group A and set up a semifinal clash with Group C winners Albirex Niigata (S).
Speaking at the post-match press conference, a victorious coach Jorg Steinebrunner was pleased that his side carried out his instructions of playing for a win instead of a draw which would have been enough for them to progress.
He said: "At 2-2, it was a fair result. In the second half, I made the intention clear that we're not going to put 11 men behind the ball and play for the draw. It's about taking care of the ball and producing good counter-attacks which we showed for the third and fourth goals."
"Today's performance was a lot about determination and not resting on possibly having that one point...In the first half we looked good while going forward but lost a bit of way after that because we did not show the same energy as DPMM."
Geylang International: Yazid Yasin (GK), Anaz Hadee, Hafiz Osman (Khairulnizam Jumahat 58'), Kento Fukuda, Syed Thaha (Huzaifah Aziz 74'), Nor Azli Yusoff, Yuki Ichikawa, Tatsuro Inui, Jozef Kaplan (C), Hafiz Nor (Shah Hirul 87'), Bruno Castanheira
Brunei DPMM: Wardun Yussof (GK), Aminuddin Zakwan, Brian McLean, Boris Raspudic, Sairol Sahari (Azwan Saleh 50'), Maududi Hilmi (Awangku Fakharazzi 78'), Joe Gamble, Rosmin Kamis (C), Najib Tarif (Shahrazen Said 78'), Paulo Sergio, Rafael Ramazotti