In Southeast Asian football, the last place you want to be when only a win will do is Bangkok. Getting to the Rajamangala Stadium can be tricky. The best way is on the back of one of the hundreds of motorbikes that hang around the closest subway station to ferry the tens of thousands that head there for the big games.
If getting there is hard, getting out with something is more difficult.
Thailand have been the region's top dogs for a few years now and, aside from a below-par performance in last week's 1-1 draw with the Philippines, are showing few signs of relinquishing that lofty position. Better teams than Singapore have struggled in the capital, but Sunday's showdown could be a turning point for the Lions. Getting a result in Bangkok would be a huge step forward for new coach Fandi Ahmad and send a huge message to the rest of the region. A win would guarantee a place in the last four; a draw will be enough should the Philippines lose in Jakarta.
For Singapore, being in contention going into the final round of games is not a bad performance for a team that found itself in the tougher of the two groups. With four teams going for the top two spots and one of those being Thailand, it was a big ask.
The performances have been encouraging. The 1-0 opening win over Indonesia, the team that dumped Singapore out of the 2016 edition, was as satisfying as it was deserved. The 1-0 loss in the Philippines was also a fair result; the Lions were competitive but did not create enough.
That loss led coach Fandi to demand a four-goal win over Timor Leste in the penultimate group game. Such a public demand is an unusual one in Singapore. Certainly predecessor V. Sundramoorthy would never have said such a thing, but it is a mark of a more aggressive and confident team.
The team responded with a 6-1 victory. The home team never stopped going forward and was full of controlled aggression. Yes, it was only Timor Leste, and a young Timor Leste at that, but this was a team that had come back from three goals down against the Philippines to lose 3-2 and give Sven-Goran Eriksson and his men a huge scare.
The 6-1 win is probably not going to be enough because the result from just outside Manila was not what coach Fandi would have wanted. The tie was a little fortunate for Thailand, but it would have suited Singapore more had the Thais hung on for the win. It would have put the Lions in second and knowing that a draw would be enough should the Philippines fail to win in Jakarta.
That deflected goal from Jovin Bevic also means Indonesia are now out -- making a Philippines point or three much likelier. The Gelora Bung Karno can create one of the best and most intimidating atmospheres in Asia, but when the game means nothing, then it loses much of its teeth.
It also means that Thailand have everything to play for. With a maximum nine points and by far the superior goal difference, a win would have virtually ensured the progress of the War Elephants. Now, they know that defeat will likely mean elimination. That, for a nation going for three AFF Cups on the trot and six in total, is unthinkable.
Singapore coach Fandi Ahmad, however, is not thinking about that.
"The last game will decide our fate, and I believe in my team," he said. "We will give the Thais a good fight, even though they are favourites. We won't depend on anybody else except ourselves. It is about time we go out there and fight for our lives."
And so Singapore go to the toughest place in Southeast Asia, knowing that they probably need a win to progress. That is a simple equation even if it is going to be the toughest task.