Harib Abdalla Suhail scored the all-important goal as the UAE stunned South Korea 1-0 on Tuesday to advance to an Asian qualifying playoff against Australia on the road to the World Cup in Qatar.

South Korea and Iran had already made the cut directly from Group A in the final round of qualifying, leaving the UAE and Iraq in a crunch battle to clinch the third spot in order to earn the right to meet Australia, who finished third in Group B.

The winners of that match will meet a South American team in an inter-continental playoff with the victors advancing to the World Cup proper.

The loss in Dubai on Tuesday was South Korea's first defeat in 10 matches as they finished second in Group A with 23 points, two behind top side Iran.

The Emiratis have been in the finals of the quadrennial showpiece only once, in 1990, and although they were allowed only a miserly 23 percent ball possession, they managed to sneak a goal through the South Korean defence in the 54th minute to grab a crucial victory and finish on 12 points.

Mohammed al-Balushi provided the assist with a headed pass and after a 40-yard run Suhail found the bottom right corner of the South Korean net with a fine left-footed shot.

The rattled South Koreans tried their utmost to find the equaliser but the hosts held firm to keep their hopes alive via the playoff route.

Iraq faced Syria a few kilometres across Dubai at the Rashid Stadium but the Iraqis fell behind in the third minute to an Alaa al-Dali goal before Aymen Hussein's 31st minute strike helped them restore parity.

Iraq would have made the playoff only if they had beaten Syria and the UAE drew with or lost to South Korea. Earlier Iran beat Lebanon 2-0 to finish in top spot with Sardar Azmoun and Alireza Jahanbakhsh on target at the Imam Reza Stadium in Mashhad.

Lebanon too had an outside chance of qualifying for the playoff if they had won and the UAE and Iraq lost on Tuesday but the hosts were too strong for them as they crashed to their sixth defeat in Group A.

Meanwhile, Saudi Arabia topped Group B after a 1-0 win over Australia saw them finish on 23 points, one point ahead of Japan.

Australia had a goal disallowed by VAR late in the first half after Martin Boyle was ruled offside in their last match in Group B in the port city of Jeddah.

The Socceroos crashed to their third defeat as they conceded a penalty in the 65th minute and Salem al-Dawsari made no mistake with his effort.

In other matches Oman finished on a high by beating China 2-0 while Japan, who have already qualified for Qatar, and Vietnam played out a 1-1 draw.

For China, who have played in the finals only once before, it was yet another disappointing qualifying campaign as they finished fifth in Group B with just one win and six defeats.