Syria claimed a flattering 4-0 win over the Lions who were missing several key players in Tehran
Played in Tehran, Iran, the match got off to a quick start with the designated home side taking an early lead.
Sanharib Malki beat a slow-to-react Singapore defence to a cross from the byline, to hit a low shot into the far corner of Hassan Sunny's goal.
The goal looked to open the floodgates for Syria, with Singapore pressed into defending inside their own half for most of the match. But the scoreline remained at 1-0 going into the break with some stubborn defending and an in-form Hassan Sunny denying the rampant Syrians.
But the cracks eventually appeared in the Singapore defence. Late into the game, when the Lions looked to have salvaged a decent result with an understrength side, Ahmad Al Doni pounced on a poor clearance to beat Hassan from close range and double the lead at the 83rd minute.
Just three minutes later another defensive lapse let in Oday Jaffal who made it a comfortable 3-0.
With the game entering added time, an unmarked Abdul Fattah Al Agha rose the highest to head home from a corner kick to seal an emphatic 4-0 win.
The defeat leaves Singapore at the foot of Group B while Syria take up third place. Both teams have two more games to go with the Lions next taking on Jordan at home in February.