Singapore could be without utility man Safuwan Baharudin against four-time Asian champions Japan in Saitama for their second 2018 World Cup Group E Qualifier on Tuesday night.
Safuwan was the star of Thursday's 4-0 win in Cambodia, scoring two first half goals.
Coach Bernd Stange confirmed that the 23-year-old Malaysia FA Cup winner with LionsXII -- who had a successful loan spell with A-League club Melbourne City earlier this year -- had flown back from Japan to attend to a family matter and is unlikely to play against the continental heavyweights.
"This is a big blow for us," said Stange. "However, the World Cup qualifiers are like a marathon. Injuries and unexpected matters such as this always come up and it is all about overcoming such problems. We are lucky that we have no injuries going into the game."
Stange looked ahead to the clash against Vahid Halilhodzic's team with utmost pragmatism.
"Japan are a great side and are well above our level," said the 67-year-old German tactician. "We've not played against such a side for a long time. Japan will have the ball all the time and will totally dominate us in possession.
"All our players want to use this opportunity to be part of a great football party and learn from the experience. They must be calm at all times, play without fear and to the best of their abilities. We'll be compact while defending as we'll not have many scoring chances. But we have players who can be effective on the counter attack."
Stange added that playing in front of a packed Saitama stadium will also be a learning experience for his side.
"This will be the third successive game that my side will be playing in front of a packed house if one were to include LionsXII's Malaysia FA Cup final as well. They did well in the two previous occasions [the Malaysia FA Cup win and Thursday's win in Phnom Penh].
"But the level of the opposition will be way too high on Tuesday -- Japan trounced strong sides such as Uzbekistan and Iraq 5-1 and 4-0 in their pre-qualifying friendlies -- and our players must remain calm in front of the 60,000 Japanese fans expected in the stadium and avoid mistakes as much as possible."
Asked what would constitute a good result for his side against the continental heavyweights, Stange said that a draw would be a difficult result to achieve.
"We will need a lot of luck to get a point," he said.
"There are very seldom cases in club football where second or third division teams upset elite champions. We are playing a Japanese side featuring players like Shinji Kagawa and Keisuke Honda who play for European heavyweights such as Borussia Dortmund and AC Milan. So we must be realistic about our chances."
Singapore have three points from their Thursday opener. Following Tuesday's game, the Lions will next play Syria away on Sep. 3.
Japan will again be at home on the same day against Cambodia for their second stop in the road to Russia 2018.