By Gabriel Tan at the Clementi Stadium
In an enthralling game at the Clementi Stadium, the Stags found themselves ahead thrice courtesy of goals from Sead Hadzibulic, Ahmad Latiff and Aleksandar Duric, but Albirex showed tremendous resolve to hit back each time, with Yasuhiro Yamakoshi racking up a hat-trick in the process.
Tampines were then reduced to ten men in the 74th minute when Mustafic Fahrudin picked up a second booking, and the visitors went on to make the numerical advantage count by grabbing the winner eight minutes from time through Sho Kamimura's close-range strike.
The result, which was only the hosts' fourth defeat of the campaign, means the White Swans are now six points off the top of the table, with three games to play. Tampines have two matches remaining.
Coming off the back of a disappointing 1-1 draw with Gombak United last Saturday, the Stags received a huge boost as Mustafic was passed fit ahead of the game despite a niggling groin injury and was immediately restored to coach Tay Peng Kee's starting XI.
Eight minutes in, Tampines got off to a dream start as Hadzibulic put them ahead, although plenty of credit has to go to Duric for his involvement in the build-up. Receiving the ball on the edge of the area with three opponents surrounding him, the Stags captain held up the ball strongly before turning towards goal, and while the ball slipped out of his control, it fell straight to his strike partner, who made no mistake in stabbing home.
Ten minutes later, Imran Sahib came close to doubling his side's lead when he unleashed a blistering 25-yard effort that was parried away by Takuma Ito, before Hadzibulic sent a left-footed strike from the edge of the box just wide with the Albirex custodian beaten all ends up.
By now, the hosts were firmly in control of the game but against the run of play, the White Swans equalised in the 29th minute when Yamakoshi tried his luck from distance with a fairly-tame effort that somehow managed to find its way past Sasa Dreven, who looked like he had been fooled by the flight of the ball.
Three minutes after the hour mark, Tampines found themselves in front again when Latiff's attempted pass in search of Duric inside the six-yard box was headed by Norihiro Kawakami straight back to him. The influential midfielder promptly latched onto the loose ball and took a touch to steady, before clinically firing past the onrushing Ito.
However, as quickly as they had regained the lead, the hosts found themselves pegged back once more in the 36th minute. Despite being aware that a crunching challenge from Benoit Croissant was beckoning, Kamimura cleverly prodded the ball into the box and found Keisuke Matsui, who - despite having plenty of the goal to aim for - opted to square a pass for Yamakoshi to sweep home at the far post.
Tay was left fuming by the sidelines at the way his side allowed their opponents to score twice in the opening 45 with their only two real forays forward, but whatever he said at the break clearly worked as his team came out for the second half raring to bite back.
Two minutes after the break, Duric made it 3-2 when he poked home from close range after good work from Latiff, who had received the ball from Imran and headed straight for the byline, before cutting a pinpoint cross back to his skipper.
Then, in the span of 20 frenetic minutes, Tampines pushed forward with intent and created a plethora of excellent chances but were just unable to find a fourth, with Gligor Gligorov, Sead Hadzibulic and substitute Jamil Ali all guilty of wastefulness.
The Stags' best chance came in the 59th minute when Duric forced his way down the right before floating a ball into the box, only to see Hadzibulic, who had shown great determination to meet the cross, head over with only Ito to beat.
Having squandered all those opportunities, a growing sense of unease began to emanate from the home crowd as they wondered if Tampines were going to pay for their profligacy.
Ten minutes after the hour mark, that almost happened when a glorious left-wing cross from Takeshi Ito was met at the back post by Yamakoshi, who did extremely well to outjump Ismadi Mukthar but could only watch on as his header came back off the woodwork.
Nonetheless, Albirex created another chance two minutes later through the same combination and this time around they got the equaliser, after the left-back received a neat pass from Kamimura and floated another lovely delivery for the unmarked Yamakoshi to power home.
Things then got from bad to worse for the Stags in the 74th minute when Mustafic, who was already on a yellow, hacked down Kamimura in full flight, leaving referee Leow Thiam Hoe with no choice but to issue him his marching orders.
And as the Stags' shoulders began to slump following the dismissal of their influential anchorman, the visitors made full use of the advantage by going on to grab what proved to be the winner in the 82nd minute.
Picking up the ball outside the opposition box, Yamakoshi ran straight at the defence before slipping it right to the rampaging Hidekazu Yamamoto. The right-back's driven shot wasn't the best-placed of efforts but it had plenty of power on it and Dreven could only push it towards the far post, where Kamimura was on hand to tap into an unguarded net.
Four minutes into injury-time, Tampines had only final chance to grab an equaliser of their own when Anaz Hadee whipped a dangerous cross from the right into the box, but with Duric and Noh Alam Shah both ready to pounce, Takuma Ito stood tall and claimed the cross with authority, as Albirex held out for the most exciting of victories and more importantly, three points that keep their title hopes alive for another week at least.
Tampines Rovers: Sasa Dreven, Anaz Hadee, Benoit Croissant, Jufri Taha, Imran Sahib, Mustafic Fahrudin, Gligor Gligorov (Jamil Ali 61'), Ahmad Latiff, Ismadi Mukhtar, Sead Hadzibulic (Noh Alam Shah 89'), Aleksandar Duric.
Albirex Niigata: Takuma Ito, Hidekazu Yamamoto, Yuki Ichikawa, Norihiro Kawakami, Takeshi Ito, Shuhei Hotta, Keisuke Matsui, Atsushi Shimono, Masatake Sato (Musashi Okuyama 90'), Sho Kamimura (Yuhei Shiratori 90'), Yasuhiro Yamakoshi.