A come-from-behind victory against a side that had conceded 16 goals ensured Dejan Gluscevic's boys avoided finishing bottom of Group H
The match held at the Thai Japanese Stadium in Thailand saw two sides who had already been eliminated from contention and were also in the hunt to grab their first goals of the competition.
With the first-half ending goalless it was Brunei, who had lost 6-0 and 7-0 in their other two games, that broke the deadlock through Mohammad Asri Haji Aspar in the 63rd minute.
However Singapore replied soon after through Brandon Koh in the 76th minute before Koh grabbed his second 10 minutes later to give the Young Lions the lead. Jonathan Tan then made it 3-1 in the 83rd minute, just moments after coming on in place of Muhammad Zulfadhmi.
With the win, Singapore finished third in the four-team Group H, with DPR Korea finishing as group winners after overcoming hosts Thailand 2-0 in the day's other match.