Back as Singapore's No. 1, Izwan Mahbud plays his part in important opening win at ASEAN Championship

But after the abrupt international retirement of Hassan Sunny earlier this year left a massive void but also a huge opportunity in the Lions goal, it is Izwan who has won the race to be the first man up at this year's ASEAN Championship.

On Wednesday, as they opened their Group A campaign after sitting out the first round of matches with a bye, Singapore grinded out a 2-1 win over Cambodia in a match that perhaps was less comfortable than it might have been.

Two glaring mistakes from opposition goalkeeper Vireak Dara gifted goals to Faris Ramli and Shawal Anuar early on, yet the hosts were unable to build on a 2-0 lead inside 16 minutes.

Instead, Cambodia were able to pull one back a minute before the hour mark -- which set the stage for a grandstand finish as the Lions found themselves under severe pressure.

Izwan was required to produce a series of smart saves, including one to deny Soknet Hav from point-blank range after a short back-pass from Safuwan Baharudin, while he also had to show authority from numerous defensive set-piece situations.

Cambodia's finishing also let them down as Singapore were ultimately able to hold out for an important-if-nervy opening victory.

"Of course, it [the final stages of the match] was quite nervous," Izwan told ESPN. "They kept attacking.

"As one of the older guys, I had to tell the players to calm down and just play our game. We should have controlled the game more and, especially at 2-0, played more to our strengths.

"In the last ten minutes, it was just about staying strong and keeping our focus and concentration on the game.

"We're grateful to get the three points but, as you can see, we've a lot of work to do. So we'll get back to the drawing board and see what we can do better."

Izwan revealed it was still a bit of a shock that he had gotten the nod ahead of Syazwan Buhari and Rudy Khairullah, who have both also been in excellent form in the Singapore Premier League with BG Tampines Rovers and Geylang International respectively.

Nonetheless, the Lion City Sailors custodian, who was the first choice in Hassan's injury-enforced absence when Singapore last won the tournament in 2012, is aware he will have to keep working hard to keep his place in the starting XI.

"To be honest, I was shocked but I'm very grateful," he explained.

"Everyone is still fighting for spots in the team, including the No. 1. We'll just have to see how it goes for the next game."

With Singapore widely expected to battle with Malaysia for a top-two spot, given reigning champions Thailand look a shoo-in, the fact that they have beaten Cambodia -- who held the Malaysians to a surprise 2-2 draw back on Sunday -- has already given the Lions a bit of an advantage.

Still, Singapore will be aware they can ill afford to underestimate Timor-Leste, who gave Malaysia an almighty scare in Wednesday's other game by leading 2-1 before ultimately succumbing to a 3-2 defeat.

"In this kind of tournament, every point is very important," Izwan added.

"We meet every team just once. We have to get any and as many points as we can.

"At home, we should be looking to get all wins. Even away, we want to win every game.

"Now, we just have to take it one game at a time. We'll put this win over Cambodia aside now and focus on Timor-Leste."