With the top seeds across the eight joint Asian Cup qualifying groups sitting out the sixth matchday, the region's unfancied sides boosted their chances of grabbing one of the 12 places on offer for the next stage of the Road to Russia 2018.
North Korea are close to doing so after Jong Il-gwan struck a 15th minute penalty for a 1-0 home win over Yemen to leave the twice World Cup qualifiers four points clear of Uzbekistan in Group H with only three games remaining.
In Muscat, Oman dispatched India 3-0 to move three points clear of favourites Iran at the top of Group D.
Iran entertained Japan in a friendly that finished 1-1 after Yoshinori Muto cancelled out Mehdi Torabi's opener for the hosts. Perennial qualifiers South Korea were 3-0 winners over Jamaica in another friendly.
With Japan in Tehran, Singapore took the opportunity to move level with the four-times Asian champions at the top of Group E after a sketchy 2-1 win at home to Cambodia, who scored their first goal of the campaign through Sos Suhana.
Singapore coach Bernd Stange was left surprised at the criticism of his side, who have aspirations of taking one of the four best runners-up places that will mean qualification for the next Asian Cup and third stage of World Cup qualification.
"Why are you not able to be happy that we have 10 points?," the German told reporters who questioned why the team made hard work of the result.
Thailand are keen not to leave anything to chance and they ramped up the pressure on favoured Iraq in Group F by claiming a 3-0 away in Vietnam to open up a five-point gap in the pool, which has been reduced to four teams following Indonesia's suspension by FIFA for political interference.
Kroekrit Thawikan hit a stunning long-range swerving opener before an own goal by Tien Thanh just before the hour mark made the game safe for the visitors, with Theerathon Bunmathan completing the scoring in Hanoi by finishing a neat team move.
Thailand face Taiwan next month before what is sure to be the decisive clash away to former Asian champions Iraq in Tehran in the battle for top spot in the group.
Southeast Asian rivals Malaysia grabbed their first World cup qualifying away win in 14 years when they edged East Timor 1-0, their opening victory in Group A.
"This is an important win. We needed it to revive our chances of finishing third in the group," interim coach Ong Kim Swee said.
There was no first point of the campaign for lowly Bhutan, however, with Hong Kong's Siu Ki Chan heading the only goal in the 89th minute winner to move the visitors clear of China in second place in Group C.
Leaders Qatar host Maldives later on Tuesday.
(Reporting by Patrick Johnston; editing by Martyn Herman)
