Holders Albirex Niigata (S) overcame Home United 5-2 on aggregate after a 2-1 win in the second leg of the semifinals on Saturday night to set up a first ever foreign final in the tournament's 20-year history.
Faris Ramli's penalty put Home within a goal of levelling the tie, but late strikes from Kento Nagasaki and Takuya Akiyama sealed the deal for the White Swans.
Albirex will face Philippines invitees Global-Cebu FC, who won 2-1 against Hougang United in Saturday night's other semifinal second-leg tie to progress 4-3 on aggregate, despite being reduced to 10 men on 70 minutes due to Dennis Villaneuva's red card.
Trailing 3-1 from the first leg, Home stuck to their ultra-offensive 4-2-4 formation at Bishan Stadium. They were largely on top in the first half, but found it tough to get past Albirex goalkeeper Yosuke Nozawa.
The former J.League custodian clawed away Stipe Plazibat's header from Hariss Harun's cross in the 14th minute, before denying Irfan Fandi in a one-on-one opportunity 10 minutes later.
Home created another excellent chance on 27 minutes with Irfan knocking on Sirina Camara's cross into the six-yard box, but no one was on hand to capitalise.
The Protectors' pressure would pay off on the stroke of half-time. Faris converted from the spot from his 19th goal of the season after an Albirex defender had handled in the box.
Albirex almost equalised on the night on 54 minutes, with Nagasaki rattling the bar from distance.
Home kept piling the pressure on in the second half and almost pulled level on aggregate in the 70th minute. But Adam somehow failed to convert his header from Aqhari Abdullah's brilliant cross into the area.
Albirex finished the game strongly though, with Home goalkeeper Hassan Sunny requiring to produce a superb double save to deny Shoichiro Sakamoto and Tsubasa Sano.
However, there was nothing the Singapore No. 1 could do to stop the Albirex late show in the final 10 minutes.
Nagasaki drove home a superb 20-yard grasscutter on 83 minutes, before centre-back Akiyama rose the highest to head home from a corner three minutes later to kill any hopes of a Home comeback.
The final whistle soon sounded as Albirex marched on to remain on course to repeat last season's feat of winning a quadruple of trophies.
Home United: Hassan Sunny (GK, C), Abdil Qaiyyim, Hariss Harun, Irfan Fandi, Juma'at Jantan, Izzdin Shafiq, Song Uiyoung (Sirina Camara 22'), Aqhari Abdullah, Faris Ramli, Stipe Plazibat, Adam Swandi (Iqram Rifqi 90')
Albirex Niigata (S): Yosuke Nozawa (GK), Tomoki Menda, Yasutaka Yanagi, Takuya Akiyama, Naofumi Tanaka, Shoichiro Sakamoto (Rui Kumada 86'), Hiroyoshi Kamata, Shuto Inaba (C), Kento Nagasaki, Ryota Nakai (Shoma Kondo 90'), Tsubasa Sano