By Gabriel Tan at the Clementi Stadium
Sead Hadzibulic handed the Stags the lead on the night in the 15th minute when he nodded home a cross from Gligor Gligorov, before Jamil Ali put the result to bed on the hour mark when he capitalised on some poor defending to grab their second.
Having claimed a 2-1 lead in the first leg at the Jurong East Stadium just four days earlier, Tampines coach Steven Tan made just one change to his starting XI by introducing Jamil for Ahmed Fahmie.
And with the slenderest of advantages to hold on to, Tampines started the game cautiously and allowed the visitors to dominate the opening proceedings, a move which nearly cost them three minutes in when Sasa Dreven was forced into a smart save to keep out a deflected shot from Toshikazu Soya.
Nine minutes later, the Albirex striker should have done better when he fired wide from twelve yards out after a dangerous cross from Sho Kamimura found its way to him at the far side of the area.
Despite struggling to get anything going in the final third, the Stags were always going to pose a threat with their height in attack and they put their aerial advantage to good use in the 15th minute, when Hadzibulic met a freekick from Gligorov and planted a firm header into the back of the net to give his side the lead.
Eight minutes later, Ahmad Latiff wasted an excellent chance to double Tampines' advantage when he fired a weak shot wide, after Jamil Ali had broken down the left on the counter and cut a precise ball back to the edge of the area.
Given their usual fast-passing style of play, Albirex were looking uncharacteristically lacklustre and struggled to create any clear-cut openings for much of the first period.
Two minutes after the break, that nearly changed when Soya went on a penetrating run through the middle and laid the ball off to Kamimura, only for the usually-clinical winger to fire a shot wide.
But right on the hour mark, the visitors all but ended their hopes of progressing to the last four when they allowed Tampines to grab a second after some comical play at the back.
Watch: Highlights: Tampines 2-0 Albirex Niigata.. More Videos
Picking up possession just inside the Albirex half, Hadzibulic floated a glorious ball over the top that Norihiro Kawakami failed to deal with, before the onrushing Takuma Ito completely fluffed his clearance, leaving Jamil with a simple tap-in.
Curiously, Albirex then started to look more adventurous even with the tie effectively over, with coach Koichi Sugiyama throwing centre-back Kunihiro Yamashita up front to add a different dimension to their attack.
Nine minutes from time, the 26-year-old nearly grabbed a consolation when he leapt well to meet a cross from Takeshi Ito and powered a header towards goal, although it was straight at Dreven, who hardly had a save to make all game long.
Ultimately, Albirex just failed to rise to the occasion when it mattered most, and it is Tampines that will now be looking forward to a last-four clash between the winners of the other quarter-final involving United Football League outfit Loyola Meralco Sparks and Myanmar's Kanbawza.
Tampines Rovers: Sasa Dreven, Anaz Hadee, Benoit Croissant, Jufri Taha, Imran Sahib, Ahmad Latiff, Gligor Gligorov, Ismadi Mukhtar, Jamil Ali (Ahmed Fahmie 76'), Sead Hadzibulic (Hairulnazri Hanafi 90'), Aleksandar Duric (Sazali Salleh 86').
Albirex Niigata: Takuma Ito, Hidekazu Yamamoto, Kunihiro Yamashita, Norihiro Kawakami, Takeshi Ito, Keisuke Matsui (Shuhei Hotta 62'), Atsushi Shimono, Musashi Okuyama, Toshikazu Soya, Sho Kamimura (Masatake Sato 67'), Yasuhiro Yamakoshi.