By Gabriel Tan at the Jurong East Stadium
Albirex went ahead in the 22nd minute when Yasuhiro Yamakoshi opened the scoring with a stunning 30-yard rocket, but the Stags came back strongly in the second half and equalised through Jufri Taha five minutes after the break, before Ahmad Latiff grabbed the winner in the 79th minute when he fired home from close range.
The victory comes as the latest in a run of impressive wins for Tampines, including triumphs over DPMM FC and Balestier Khalsa, which has seen Steven Tan's men climb up to joint-top in the Great Eastern-YEO's S.League.
Albirex also headed into the game as one of the form teams in the competition, having gone their last seven league games without defeat, and it was them who started the brighter of the two sides as they dominated early proceedings with their trademark fast-passing game.
Nonetheless, the visitors eventually got into the groove of things and carved out the first real opening in the 21st minute when Sead Hadzibulic threaded a neat pass through to Ahmed Fahmie, only for the 25-year-old to scuff a left-footed attempt wide.
A minute later, Albirex made Tampines pay for that miss when Yamakoshi opened the scoring, although there appeared to be no apparent danger when he picked up the ball 30 yards out from goal. But with few options ahead of him, the Japanese forward let fly with a ferocious effort that dipped just inside the top corner, leaving opposition keeper Sasa Dreven with no chance whatsoever.
Nine minutes later, Yamakoshi wasted an excellent chance to double his tally when he lashed a shot just over after a terrific passing move saw Sho Kamimura play him in with a clever backheel.
By now, Tan could be seen cutting a frustrated figure down the touchline as his strike trio of captain Aleksandar Duric, Hadzibulic and Fahmie failed to show any signs of a connection, an issue he immediately sought to address by replacing the latter with Jamil Ali shortly after the half-hour mark.
A minute after he came on, Jamil made an instant impact as he was tugged back inside the Albirex area after pouncing on a loose ball, leaving referee K. Kalimuthu little choice but to award a penalty. Unfortunately for the Stags, Hadzibulic, who scored two goals in his last outing against Balestier, saw his well-struck effort kept out by a flying save from Takuma Ito.
However, it only took the Serb five minutes after the restart to make amends when he met a freekick from Gligor Gligorov at the far post and nodded it back across the face of goal, where Jufri was on hand to poke home the equaliser.
Despite losing their lead, the White Swans continued to dominate the possession stakes but seemed to lack a clinical edge as they struggled to create any real openings. The closest they came to carving open the Tampines backline was when Kamimura dinked a clever ball through to Yamakoshi in the 52nd minute, although Dreven did well to race of his line and block the effort.
Watch: Highlights - Albirex Niigata 1-2 Tampines... More Videos
Six minutes later, Yamakoshi was presented with another chance as a cross from the right by Masatake Sato was cleared straight into his path but from just inside the area, he could only manage to fire straight at the Tampines custodian.
11 minutes from time, the hosts were made to rue their inability to convert their possession into goals as a slip from Kunihiro Yamashita allowed Duric to steal possession just inside the Albirex half and head straight for goal. With several team-mates racing forward in support, the veteran striker picked the right option as he laid the ball to Latiff, who made no mistake from eight yards out to put his side in front.
And deep into stoppage time, Jamil, who had been very impressive after coming on for Fahmie, could have effectively ended the tie when he raced through on goal and smashed an effort just wide, although that would have been cruel on Albirex.
Instead, there is still plenty left to play for as Tampines take a one-goal lead back to the Clementi Stadium for Friday's second leg.
Albirex Niigata: Takuma Ito, Yuki Ichikawa, Kunihiro Yamashita, Norihiro Kawakami, Takeshi Ito, Shuhei Hotta, Atsushi Shimono, Musashi Okuyama, Masatake Sato (Keita Kobayashi 78'), Sho Kamimura, Yasuhiro Yamakoshi (Toshikazu Soya 84').
Tampines Rovers: Sasa Dreven, Anaz Hadee, Benoit Croissant, Mustafic Fahrudin (Jufri Taha 1'), Imran Sahib, Gligor Gligorov, Ahmad Latiff, Ismadi Mukhtar, Ahmed Fahmie (Jamil Ali 32'), Sead Hadzibulic (Sazali Salleh 90'), Aleksandar Duric.