By Gabriel Tan at the Jalan Besar Stadium
Tales dos Santos opened the scoring after just ten minutes when he leapt highest to nod home a corner from Azwan Saleh, before substitute Adi Said wrapped up the win in the 79th minute when he raced through on goal and coolly slotted past Shahril Jantan.
To add insult to injury, Warriors substitute Ruzaini Zainal was then handed his marching orders in the dying moments of the match after he appeared to lash out at Subhi Abdilah, capping a miserable day for his side.
Despite having been taken to extra-time and penalties by Home United in their quarter-final encounter last Saturday, DPMM coach Vjeran Simunic opted for the same line-up he named against the Protectors, apart from Azwan who replaced the injured Pg Sallehuddin Damit.
SAFFC, on the other hand, managed to win their last-eight clash against Hougang United in regulation time, thanks to Shimpei Sakurada's 90th-minute winner, but Warriors boss still Richard Bok opted to make two changes to his starting XI, bringing Mislav Karoglan and Eddie Chang in for Marin Jonjic and Razaleigh Khalik respectively.
Six minutes in, Karoglan had the first chance to break the deadlock when he was played in behind the visitors' backline by Aliff Shafaein, but the Croatian marksman could only blaze over from a tight angle.
Yet before either side could really settle, DPMM stunned their opponents by taking the lead four minutes later when Azwan whipped an inswinging corner straight onto the head of Dos Santos, who proceeded to plant a bullet header in off the crossbar.
Three minutes before the half-hour mark, the Bruneian outfit nearly doubled their lead when captain Rosmin Kamis went on a driving run through the middle before playing the ball to Patrick da Silva, who fired in a ferocious shot that stung the hands of Shahril.
Ten minutes later, Da Silva decided to try his luck again - this time from further out - and Shahril once again had to react quickly to prevent the effort from sailing in under the crossbar.
But despite being pegged back for much of the opening period, SAFFC began to come to life in the closing stages of the half and they were unlucky not to equalise in the 39th minute, when sloppy defending from DPMM allowed Karoglan to steal possession just outside the area and slip Aliff in down the left.
The former Tanjong Pagar United raced towards the byline before delivering a perfectly-weighted cross onto the head of Fazrul Nawaz, only for the Singapore international to send his header back off the crossbar.
However, Simunic's charges failed to clear the resultant loose ball, allowing the Warriors to play it back into the box where Inui cut in from the right, before curling in a shot that forced Wardun Yussof into an excellent one-handed stop.
Despite going in ahead at the break, DPMM were handed a huge blow five minutes into the second half when Basiru Osman had to be replaced after appearing to be unconscious following a heavy collision with Marin Vidosevic.
Still, they didn't show any signs of missing their star man in the final third, and could have edged further ahead in the 61st minute when SAFFC captain Daniel Bennett had to put in a sliding block to deny Da Silva, who had found space inside the area after a neat interchange of passes with Shahrazen Said.
Fourteen minutes from time, DPMM failed to make another glorious opportunity count after a lapse in concentration from the Warriors defence allowed Awangku Fakharazzi to sneak in behind them, but he narrowly failed to connect with a Shahrazen cross when the slightest of touches would have most likely seen him find the back of the net.
Nonetheless, there was to be no denying them three minutes later when Shahrazen played a visionary pass through to his brother Adi, who raced towards goal before sliding his shot under Shahril just four minutes after coming on.
The trick nearly worked again five minutes later although this time it was Rosmin Kamis who was sent through by the DPMM forward. On this occasion, Shahril raced out in time and beat the opposition skipper to the ball but directed his clearance straight to Ivan Jerkovic, who looked set to send a lob into the unguarded net, only for Bennett to race back in time and chest the ball to safety.
In one final bid to grab a goal, Bok decided to throw Vidosevic up forward to add some strength and height to his attack but the move failed to reap any rewards as their opponents repelled everything that came their way.
And as SAFFC's frustrations began to boil over, they found themselves reduced to ten men after Ruzaini was handed a straight red for kicking out at Subhi, capping a forgettable day at the office.
SAFFC: Shahril Jantan, Eddie Chang (Razaleigh Khalik 46'), Daniel Bennett, Marin Vidosevic, Noh Rahman, Tatsuro Inui, Shukor Zailan, Shimpei Sakurada, Aliff Shafaein, Fazrul Nawaz (Ruzaini Zainal 66'), Mislav Karoglan.
DPMM FC: Wardun Yussof, Shahrulrizal Abd Rahman, Tales dos Santos, Sairol Sahari, Subhi Abdilah, Azwan Saleh, Rosmin Kamis, Ivan Jerkovic, Shahrazen Said (Suhaime Yussof 90'), Basiru Osman (Awangku Fakharazzi 52'), Patrick da Silva (Adi Said 75').