The virus-stricken forward was only named as a sub and the Stags were unable to break down a stubborn Jaguars defence as a result.
In less than 30 minutes of action, Duric hit twice to kill off the Jaguars who were threatening to hold off the Stags after Shamil Sharif had scored the equaliser for the home side.
Shahdan Sulaiman had given the Stags the lead from a spotkick.
The Warriors keep up the pressure on the leaders by defeating Balestier Khalsa 1-0 at Choa Chu Kang with their top scorer Mislav Karoglan notching the winner.
In other matches, Albirex Niigata (S) defeated Courts Young Lions 4-2 and Geylang United defeated Gombak United 1-0.
The Jurong East match was noted for Khariul Nizam return, after an eight-month suspension, and the forward make his return with a superb goal which showcased his class.
The 20-year-old beat his defender before coolly slotting it under the keeper when others will have been tempted to use power.
But it was not enough to stop the White Swans as an own goal plus Bruno Castanheira scoring along with a brace from Tatsuro Inui was enough to secure the win.
Syafiq Zainal had scored the opener for the Cubs.
Vasile Ghindaru was the scorer in the Geylang United-Gombak United game.
After that, on June 6, Albirex Niigata (S) defeated TPUFC 2-1 with Bruno Castanheira notching a brace while Hyun Jong Woon reply for the Jaguars.
TPUFCRidhuan Barudin (GK), Khairul Solyhin (Abdul Rahman), Kim Seong Kyu (C), Benedict Low, Delwinder Singh, Sudhershen Hariram (Ganesan s/o Devadas), Justin Khiang (Shamil Sharif), Kim Jong Oh, Hyun Jong Woon, Takaya Kawanabe, Patrick Paran
Alimin Mohamed (GK), Benoit Croissant (C), Seiji Kaneko, Ahmad Latiff, Akihiro Nakamura, Shahdan Sulaiman, Imran Sahib, Ismadi Mukhtar, Park Yo Seb, Shukor Zailan (Jamil Ali), Ahmed Fahmie (Aleksandar Duric)
Shahril Jantan (GK) (C), Shaiful Esah, Hafiz Osman, Bah Mamadou, Daniel Bennett, Noh Rahman, Ivan Jerkovic, Rhysh Roshan Rai (Daniel Hammond), Mislav Karoglan, Fazrul Nawaz (Syaiful Iskandar), Erwan Gunawan (Ruzaini Zainal)
Joey Sim (GK), Anaz Hadee, Lim Young Woo, Paul Cunningham (C), K Sathiaraj, Ishak Zainol, Shamsurin Abd Rahman (Vahid Bogucanin), Ridhwan Osman, Poh Yi Feng (Armanizam Dolah), Andrew Tan, Kim Young Kwang
Yazid Yasin (GK) (C), Sofiyan Abdul Hamid, Adrian Dhanaraj, Joo Ki Hwan, Syed Fadhil, Vasile Ghindaru (Shah Hirul), Kim Jae Hong (Mubarak Ahamad), Syed Thaha, Rizawan Abdullah (Jonathan Xu), Jung Hee Bong, Hafiz Rahim
Zakariah Nerani (GK) (Lee Heng Huat), Jaslee Hatta (C), Hamqaamal Shah, Ismail Yunos, Obadin Aikhena, Walid Lounis, Tengku Mushadad, Aloysius Yap (Zulkiffli Hassim), Park Kang Jin, Fareez Farhan (Kwon Jin Sung), Chang Jo Yoon
Courts Young Lions
Izwan Mahbud (GK), Eddie Chang (Afiq Yunos), Safuwan Baharudin (C), Shakir Hamzah, Fazli Ayob, Eugene Luo, Zulfahmi Arifin, Faris Ramli (Fairoz Hasan), Nazrul Ahmad Nazar, Safirul Sulaiman (Khairul Nizam), Syafiq Zainal
Ridhuan Barudin (GK), Kim Seong Kyu (C), Arisman Arman, Delwinder Singh, Kim Jong Oh, Hyun Jong Woon, Takaya Kawanabe, Israel Tan (Justin Khiang), Nurizam Azman, Gary Loo (Khairul Solyhin), Shamil Sharif (Azlan Alipah)