By Gabriel Tan at the Rizal Memorial Stadium
The result means there is still all to play for when both sides meet in Wednesday's second leg at the Jalan Besar Stadium, but it could have been so different had it not been for the Lions' wasteful ways, with captain Shahril Ishak's 26th-minute miss the pick of the bunch after he fired wide from close range when faced with an open goal.
Having been on the losing end in their last two previous encounters earlier in the year, Singapore looked hungry to make amends from the start and fashioned their first chance in the third minute when Shahdan Sulaiman blazed over from 12 yards, after Aleksandar Duric had flicked a Shaiful Esah corner into his path.
The Lions were certainly enjoying the better of the proceedings early on, while Philippines were restricted to whipping in a couple of hopeful freekicks that were easily dealt with by the opposition defence.
Khairul Amri, who was handed another chance to impress after starring in Singapore's 4-3 win over Laos, then had his first sighting at goal in the 17th minute when he latched onto a hopeful long ball by Daniel Bennett after sneaking in behind Rob Gier, only to see his snapshot pushed wide by Eduard Sacapano.
Three minutes later, the Azkals finally carved out their first chance when Angel Guirado found Phil Younghusband inside the area with a neat through-ball, but the 25-year-old had to get his shot away first time and it was comfortably smothered by Izwan Mahbud.
Shahril, who is currently the tournament's top scorer with four goals, then wasted a terrific chance to break the deadlock in the 26th minute when a cross-cum-shot by Duric beat Sacapano and dropped right at his feet at the far post, but with the entire goal to aim for, the Singapore skipper inexplicably prodded his shot wide.
Shahril was starting to give the hosts a real headache in their defensive third and he nearly presented Amri with an easy chance four minutes after the half-hour mark when he tore down the right and drilled a cross into the box, but Sacapano did well to smother before it could reach his unmarked opponent.
By now, the visitors were really threatening to grab a vital away goal and four minutes after the break, Amri was unlucky not to do so when he lined up a freekick on the edge of the box and had Sacapano scrambling with a strike that sailed just over.
Five minutes later, another golden opportunity went begging for the Lions as Shahril went on a jinking run down the right and floated a clever ball to the back bost, only for Duric to nod wide after comprehensively beating Gier in the air.
The numerous close shaves appeared to have finally stunned the hosts into life and in the 56th minute, Phil Younghusband skipped past Baihakki Khaizan on the left wing and fired in a low cross, only for Safuwan Baharudin to boot away the danger.
Philippines then came even closer to taking the lead against the run of play 12 minutes after the hour mark when Paul Mulders curled a lovely freekick just wide with Izwan beaten all ends up, after Mustafic Fahrudin had felled Guirado on the edge of the box.
Four minutes later, the Lions did however have one final chance to grab the win when Sacapano spilled a routine catch from an Amri volley inside his six-yard box, but thankfully for the Philippine Army custodian, Juan Luis Guirado was on hand to hack the ball away from the danger zone, leaving the visitors to rue their profligate ways.
Philippines: Eduard Sacapano, Carli de Murga, Rob Gier, Juan Luis Guirado, Dennis Cagara (Jeffrey Christiaens 87'), James Younghusband, Jason de Jong (Marwin Angeles 46'), Paul Mulders, Patrick Reichelt (Emelio Caligdong 77'), Phil Younghusband, Angel Guirado.
Singapore: Izwan Mahbud, Daniel Bennett, Baihakki Khaizan, Safuwan Baharudin, Shaiful Esah, Khairul Amri (Fazrul Nawaz 78'), Isa Halim, Mustafic Fahrudin, Shahdan Sulaiman, Shahril Ishak, Aleksandar Duric.