A heroic display from Mohamad Izwan bin Mahbud frustrated Japan as Singapore claimed a surprise goalless draw in Tuesday's 2018 World Cup qualifier in Saitama.
Singapore are 102 places below Japan in the FIFA world rankings, but secured a point to ensure they top Group E after beating Cambodia 4-0 last week.
Japan were unable to start their qualifying campaign with a win thanks in no small part to a fine display from Singapore goalkeeper Mahbud.
Shinji Okazaki was twice denied by the impressive Mahbud in a one-sided first half, before Okazaki and Keisuke Honda were also thwarted by fine stops from the Singapore keeper.
Honda's long-range free-kick struck the crossbar as Japan's frustration mounted and Singapore held on for a precious point.
Afghanistan beat Cambodia in the other Group E encounter, Mustafa Zazai notching the only goal of the game.
Guam made it two wins out of two to sensationally go top of Group D as India were consigned to a 2-1 defeat.
With a population of only 150,000 compared to in excess of 1.25 billion who reside in India, Guam were not expected to follow up their win over Turkmenistan by claiming another three points, but Gary White's side rose to the occasion again.
Brandon McDonald and Travis Nicklaw put Guam - ranked 174th in the world - two goals up after an hour and although Sunil Chhetri pulled a goal back in stoppage time, India were unable to avoid returning home with their heads hanging in shame.
It was also a day to forget for Iran, as Ruslan Mingazow's goal on the stroke of half-time ensured Turkmenistan held Carlos Queiroz's side to a 1-1 draw at the Dasoguz Stadium.
Australia made a winning start to their qualifying campaign with a 2-1 victory over a spirited Kyrgyzstan in Group B.
The Asian champions were far from their best in their opening game of the group, but goals in each half from Mile Jedinak and Tommy Oar secured three points. Bangladesh and Tajikistan drew 1-1 in the other Group B encounter.
Lee Jae-sung and Son Heung-min were on target as South Korea defeated Myanmar 2-0 in their Group G opener, while Lebanon put a defeat to Kuwait behind them by seeing off Laos by the same scoreline away from home.
Omar Abdulrahman scored the only goal of the game 10 minutes from time as Group A favourites United Arab Emirates edged out Timor-Leste. Palestine hammered Malaysia 6-0 and top that group on goal difference.
Yang Xu scored a hat-trick as China won 6-0 in Bhutan in Group C, with Hong Kong making it two wins out of two by getting the better of the Maldives 2-0.
North Korea and the Philippines have claimed six points out of six in Group H after beating Uzbekistan and Yemen 4-2 and 2-0 respectively. Thailand have made a perfect start in Group F, beating Chinese Taipei on the back of their win over Vietnam.
