The striker's goals added on to Shimpei Sakurada's opener as the uniformed giants saw off their Bruneian visitors
Midfielder Shimpei Sakurada and Karoglan gave the home side a comfortable 2-0 lead before the visitors pulled one back through Tales Dos Santos before half-time, but there was no denying the Warriors as Karoglan sealed the victory early in the second half.
The Warriors dominated proceedings right from the kick-off as the Bruneians were made to chase shadows by their slick passing and movement, and Alex Weaver's side were nearly rewarded after just four minutes into the game.
Hitman Karoglan's brilliant turn off a long ball was followed by a shot, but his effort went straight into the arms of DPMM goalkeeper Wardun Yussof.
Midfield lynchpin Shi Jiayi was pulling all the strings in the middle of the park and his perfectly weighted half-volleyed through ball found Karoglan, who disappointed the crowd with a scuffed effort wide off the post.
There was no sign of a DPMM goal with Rodrigo Tosi being their best player by far, holding up the ball single-handedly at every possible opportunity.
But the Warriors found their deserved breakthrough in the 27th minute. A corner from the right by Tatsuro Inui found Sakurada, whose header in a crowded box bounced off the ground and into the top left corner of the net.
Vjeran Simunic’s side barely had any time to regroup before the home side made it 2-0 just five minutes later.
Great movement and play on the right saw Jeremy Chiang played through on goal and the defender's cut back into the box was expertly converted by Karoglan.
It looked like a drubbing was on the cards for the Bruneians, who had no answer to the Warriors' dominance.
But they stunned the home crowd two minutes later by pulling one back.
A quick freekick gave right back Suhaime Yussof a chance to cross and the 32-year-old obliged with a ball across the face of the goal, which found an unmarked Dos Santos for the simplest of tasks to chest it into the goal.
It was game on in the second half with the Wasps' tails up after their goal, but the Warriors continued their dominance after the break.
In the 52nd minute, Brunei's hopes of getting back into the game were dealt another blow. Great work on the right yet again by Inui saw the winger deliver a pinpoint cross for Karoglan to double his tally and restore his side's two-goal lead.
Shi nearly put the nail in the coffin just four minutes later. A cleared corner found the midfielder, whose shot looked bound for the bottom corner before it was somehow cleared off the line.
The visitors began to find more joy in attack as they searched for a way back into the game and they nearly did in the hour mark.
A long freekick from DPMM captain Rosmin Kamis found an unmarked Adi Said, who had only the goalkeeper to beat, but he could only flick his header just wide.
The visitors continued to pour forward as the Warriors were happy to soak up the pressure.
Simunic’s side had another great chance five minutes later as Arturas Rimkevicius terrorised the Warriors defence on the right and cut the ball back for Helmi Zambin, whose shot was well blocked by custodian Hassan Sunny.
It was chances galore for DPMM in the final minutes of the game as Hassan pulled out some save after save to deny the visitors and help his side to all three points.