Shahdan Sulaiman, playing in his last match for the Stags before joining Courts Young Lions due to 'national interest', notch the winner.
This victory allowed the Stags to close the gap on Home United to two points at the top.
In other matches, Albirex Niigata (S) crushed Hougang United 5-1 while TPUFC drew 0-0 with Gombak United.
Shotaro Ihata, with a hat-trick, Atsushi Shimono and Yosuke Saito got the goals for the White Swans while Vitor Borges notch the sole goal for Hougang.
Fadhil Salim (GK), Lau Meng Meng, Shahril Alias (Fathi Yunus), Ratna Suffian (C), Azhar Sairudin (Mamadou Diallo), Jordan Webb, Fazli Jaffar, Faizal Amir (Noor Ali), Carlos Delgado, Aqhari Abdullah, Vitor Borges
Hafez Mawasi (GK), Benoit Croissant, Seiji Kaneko, Fahrudin Mustafic, Ahmad Latiff, Akihiro Nakamura, Shahdan Sulaiman (Firdaus Kasman), Ismadi Mukhtar, Aliff Shafaein (Jufri Taha), Shukor Zailan (Jamil Ali), Aleksandar Duric (C)
Ridhuan Barudin (GK), Kim Seong Kyu (C), Arisman Arman (Nurizam Azman), Delwinder Singh, Kim Jong Oh, Cyril Bagnost, Takaya Kawanabe, Israel Tan (Taufiq Rahmat), Azlan Alipah, Gary Loo, Hafiz Nor (Ganesan s/o Devadas)
Zaiful Nizam (GK), Hamqaamal Shah, Jeremy Chiang, Ismail Yunos, Obadin Aikhena (C), Walid Lounis, Tengku Mushadad, Park Kang Jin, Ridwan Jamil, Fareez Farhan (Farouq Farkhan), Chang Jo Yoon (Ruhaizad Ismail)