Qahtan Chitheer's Iraq side only had an outside chance of advancing coming into the match, but a Taichi Hara brace and goals from Yuta Taki, Kyosuke Tagawa and Koki Saito put paid to their slim hopes.

The defending champions had been anointed as Group B winners before the Matchday Three clash, but they ensured they will enter the knockout stage as the competition's form team with another commanding display.

Iraq needed to win and hope for a draw between Thailand and DPR Korea to keep their slim quarter-final hopes alive, but they squandered a golden early chance when Hasan Abdulkareem found himself through on goal only to be denied by goalkeeper Keisuke Osako.

Requiring a win to remain in contention ahead of the match, the result – coupled with table-topping Japan’s defeat of Iraq in the group’s other game – saw Thailand move through to the last eight at the expense of third-placed DPR Korea who had needed a victory of their own to guarantee their progress.

Ithsara Sritharo’s young charges will now meet Group A winners Qatar in what promises to be an enticing last eight encounter at Jakarta's Gelora Bung Karno Stadium on Sunday.

The 17-year-old pounced on a heavy touch by Emirati stopper Yousef Ali to slam home his third goal in as many matches but despite his key role in the 1-0 victory, Witan said every member of the team had played their part.

"I'm happy that we are through to the last eight, but it can only happen because of the combined effort and the hard work from everyone in the team," he said after being named Player of the Match.

"I would also like to give my biggest appreciation to the fans who have always been there for us, and this is certainly for them as well."

The Garuda Muda were heavy underdogs against the previously unbeaten Emiratis, but a 23rd minute Witan Sulaeman strike carried the hosts to a first appearance in Asia's final eight in 40 years.

The second half sending off of Nurhidayat Haji Haris made their task even more arduous, but Indonesia claimed a famous victory, one which delighted their 55-year-old boss.

The West Asians’ 4-0 win over Chinese Taipei on Wednesday rounded off a group stage campaign that began badly with a defeat to the United Arab Emirates, before a sensational 6-5 victory against host nation Indonesia on Matchday Two brought the 2014 champions back into contention.

In the end, and with three teams level on six points, Qatar assumed pole position in Group A by the narrowest of margins after scoring more goals than either second-placed Indonesia or the eliminated United Arab Emirates in the games between the trio.

With a single point from their first two matches, the Hairmau Muda must beat China PR at Pakansari Stadium and hope Tajikistan simultaneously suffer defeat to Saudi Arabia to keep their knockout stage chances alive, but hope springs eternal for Hodak.

"I always believe," he said. "I believe we can be champions. In football anything is possible. The ball is round.

"If we want to go through, we need to win and we need the result. Saudi Arabia need to win to be on the top of the table, maybe one point is good enough for them also, but Tajikistan want to win to get an easier opponents in the second round. This doesn't depend on us."

The West Asians join Group B leaders Japan as sides to have already stamped their ticket to the quarter finals, after they defied monsoonal rain to beat now eliminated China PR 1-0, thanks to Abdulmohsen Al Qahtani's late goal.

"It was a great match and the Chinese team was very, very strong. They played very well and showed a lot of skill during the match," Abdullah Atawi  said in reflection.

"The circumstances of the weather affected our performance. We had hoped we'd be better than this but this situation is what affected us, but we got the points and that's the most important thing from the match."