The Cubs crashed out of the qualifiers for the 2014 AFC U16 Championships after going down 3-1 to Australia in their final group game
The Cubs needed a win and had to hope that Chinese Taipei overcame hosts Hong Kong to stand a chance of making it to the tournament proper as one of the best runners-up.
But a dominant Australia side, who ended the qualifiers on a perfect note, kept Singapore at bay for most of the match, and were 2-0 up by the 16th minute.
Charlie Robert opened the scoring in the 13th minute before Nicholas Anthony grabbed the second three minutes later.
Singapore managed to get a goal back before the break through Haiqal Pashia, but the two-goal deficit was restored just before the hour mark as Jackson Bandiera grabbed Australia's third from the penalty spot.
Hong Kong who beat Chinest Taipei 3-1 finished second in Group G.