By Gabriel Tan at the Jalan Besar Stadium
Mustafic Fahrudin scored the only goal of the game in the 41st minute when he successfully converted from the spot to hand all three points, although even a loss would have been enough to see them win the Great Eastern-YEO's S.League title after second-placed DPMM FC fell to a 2-0 home defeat to Balestier Khalsa.
The victory also ensured the Stags ended what has been a testing campaign on a high, especially after the heartbreak of losing to SAFFC in the RHB Singapore Cup final with a last-gasp 2-1 defeat last Sunday.
Harimau, on the other hand, remain ahead of fourth-placed Albirex Niigata on goal difference and will have to wait till the White Swans play on Sunday to find out if they will finish in the top three in an impressive debut season in Singapore's top flight.
Needing to go all out for the win to guarantee the title, Tampines coach Tay Peng Kee kept to his promise of fielding an attacking line-up from the get-go by naming Aleksandar Duric, Noh Alam Shah and Sead Hadzibulic in his starting XI.
Eight minutes in, the former two nearly combined to good effect when Duric found space down the left and picked out Alam Shah in the box, only for the ex-Singapore captain to rush his shot and sent a volley way over.
The roles were reversed in the 16th minute when Alam Shah floated a lovely ball to his captain, who advanced into the box but could only manage to fire straight at Izham Tarmizi.
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Despite the hosts creating the better chances in the opening exchanges, Harimau were enjoying the lion's share of possession and a searching cross by D. Saarvindran in the 19th minute was desperately cleared away by Anaz Hadee before Ahmad Hazwan could pounce.
Two minutes later, Stags goalkeeper Sasa Dreven was called into his first real action when he had to react promptly to gather a well-struck shot by Wan Zaharulnizam, who had created a good opening for himself after going on a mazy dribble past two opponents.
Tampines however did eventually find their rhythm and started to string some good passing moves together and five minutes after the half-hour mark, they had the ball in the back of the net after Duric latched onto a visionary pass by Anaz and drilled and effort into the bottom corner, only for it to be ruled out for offside.
Six minutes before the break, the visitors' backline was carved open once more by another brilliant passing move by the defending champions, with Mustafic initiating proceedings with a penetrating pass to Hadzibulic, who in turn played a slide-rule ball to Duric.
The 42-year-old made his way into the box before going down under a challenge from Shahrul Saad and straight away, referee Leow Thiam Hoe pointed to the spot, allowing Mustafic to step up and sent the ball past a wrong-footed Izham.
Dreven, who was having a relatively error-free outing, then nearly cost his side their lead in the 50th minute when he spilled a well-placed freekick from Syahid Zaidon. Thankfully for him, there was no opposition player on hand to pounce on the rebound and he was able to gather at the second attempt.
Ten minutes later, Syahid tried his luck again with a 25-yard effort that the Croatian goalkeeper was equal to, but it was Tampines who came excruciatingly close to grabbing a second in the 65th minute when Latiff latched onto a neat ball by Hadzibulic, before sending a cross-cum-shot just wide of the top corner.
As the clock ticked down, Tay's men looked increasingly content to sit back and hold on to their lead, inviting the Malaysian outfit to show more attacking intent.
Nonetheless, Harimau's search for an equaliser meant they started leaving gaps at the back and they were nearly caught out in the 80th minute when Duric picked out possession near the halfway line and struck a killer 40-yard ball in search of Jamil Ali, only for the excellent Amer Saidin to weigh in with a vital interception before the Stags substitute could race clean through.
The Young Tigers did have one final chance to steal a share of the spoils two minutes from time when V. Kavichelvan delivered a pinpoint corner onto the head of Amer, but his firm header was deflected just wide of the far post, and as Leow blew the final whistle, it was the Tampines players who were left celebrating a second successive title.
Tampines Rovers: Sasa Dreven, Anaz Hadee, Benoit Croissant, Jufri Taha, Ahmad Latiff, Mustafic Fahrudin, Imran Sahib, Ismadi Mukhtar, Aleksandar Duric (Fazil Zailani 90'), Noh Alam Shah (Jamil Ali 62'), Sead Hadzibulic (Ahmed Fahmie 86').
Harimau Muda: Izham Tarmizi, Ariff Farhan (Azzizan Nordin 77'), Amer Saidin, Shahrul Saad, Nazirul Naim, Irfan Fazail, Syahid Zaidon, D. Saarvindran, Ferris Danial (V. Kavichelvan 83'), Wan Zaharulnizam, Ahmad Hazwan.