An Ahmad Latiff screamer after 62 minutes resurrected the Stags' title ambitions with Home now having it all to do in their final league match, having lost the iniative and with events now out of their hands.
The result meant that the Stags usurped the Protectors at the summit of the league table, with Tampines now leading the pack with 75 points, a mere point ahead of Home.
With just a single league game to go, the fight for the league championship will go right down to the wire as Tampines face off with Balestier Khalsa in their penultimate fixture while Home tackle Geylang United in their deciding league tie.
Any hopes of a free flowing and mesmerizing encounter between the top two sides were dashed after rain throughout the day rendered the pitch barely playable.
Proceedings were scrappy throughout the encounter as players struggled to bring the ball into control in a waterlogged pitch.
Both Tampines and Home attempted to launch their attacking forays via their fullbacks with both sides unable to wrestle control of the match, especially in the middle of the park.
Tampines fashioned their first real chance of the match in the 21st minute when a whipped corner was majestically met by stopper Jufri Taha but alas, his header sailed over the bar
In the 25th minute, a marauding run by right back Masrezwan Masturi saw him pick out Canadian winger Sheriff-El-Masri on the left flank and he unleashed a rasping drive which just flashed past the post.
Two minutes later, some enterprising play between Ahmad Latiff and Aleksandar Duric saw the latter release the ball to Japanese anchorman Akihiro Nakamura, who let fly outside the box but the midfielder's attempt flew way over the bar
Duric missed an absolute sitter in the 38th minute when Imran Sahib broke through down the right flank and laid the ball back for the Singaporean forward but he skewed his effort over the bar, much to his frustration.
Home honcho Lee Lim Saeng rang the changes at the interval with Yasir Hanapi entering the fray in place of midfielder Firdaus Idros.
However, it was Tampines who nearly drew first blood in the 49th minute when a jinking run and teasing cross by Imran was toe poked towards goal by Home centreback Valery Hiek but an alert Lionel Lewis was on hand to stop the ball from spilling in and he collected it gratefully.
It did not take long for Home tactician Lee to make another substitution as he threw on former Tampines forward Qui Li in place of Masrezwan on 54 minutes as Home attempted to add some attacking impetus into their game.
Knowing that nothing less than a victory would resurrect their title ambition, Stags chief Steven Tan then made his own change on the hour mark when he introduced the nippy winger Jamil Ali in place of Firdaus Kasman.
The tactical masterstroke paid instant dividends two minutes later when Jamil's delightful back flick from a corner found mercurial midfielder Ahmad Latiff, who strode just outside the penalty box and unleashed a corker of a strike which sailed past a sea of Home defenders and past Lewis' desperate dive.
His strike drew frenzied celebrations from the goalscorer, who ripped off his shirt and threw it into the stands, prompting wild scenes of jubilation from the Tampines faithful, earning the player a yellow card in the process.
Protectors gaffer Lee then withdrew the disappointing El-Masri in place of Sufian Anuar in the 70th minute as a shell-shocked Home outfit desperately tried to regain a foothold of the game following Latiff's opener.
Home then thought they had equalized in the 71st minute when Yasir Hanapi scored but the assistant referee had already flagged for offside, much to the away side's despair.
Knowing fully well that a defeat would have devastating repercussions, the Protectors desperately threw themselves in the final third in order to raid an equalizer but the Stags' rearguard held firm, defending heroically with players throwing their bodies into crosses and shots.
The dejected body language of the Home players said it all at the final whistle with players slumping to the ground and on their knees after the final whistle while jubilant scenes erupted amongst the Tampines players, who now control their title destiny.
Stags chief Steven Tan was a relieved man after the final whistle, with the result meaning that a positive result in their last league outing would see them crowned as champions.
"The fate is in our hands now and it is up to us to win the title," Tan remarked.
"It was a very decisive match and the players knew how big this match was but we will still come back to training on Thursday ahead of our match on Sunday."
"The players showed the hunger and desire and they fought for every ball and I told them at half-time if we keep working hard, we will get chances to score."
"Towards the end, we gave Home too much space and they attacked for the last five minutes but defensively, we were very good."
His counterpart, Home boss Lee could not hide his anguish at the final whistle but revealed that he wanted his players to zone out their disappointment.
"I hope the players are not thinking about the match and the lost and that they are resting," he added.
"We will talk about the match on Thursday."
Having been forced to sit in the stands following his suspension, he said that he had "big pains."
"We can lose the game but I have big pains as to why I could not sit on the bench during the game."
Home now must hope that Tampines lose their final league match against Balestier while they record a win against Geylang.