The vital three points means the Green Falcons will join the Japanese in Russian Federation, while Australia are sent to the playoffs.
Photo: Socceroos v Thailand (Reuters).
But the Saudis had a +7 goal difference as compared to Australia's +5, which was enough to send them through.
Korea nearly went in front in just the second minute. Australia hit the post three times until Tom Juric broke the deadlock in the 69th minute. Pokklaw Anan scored in the 82nd minute to break Aussie hearts, before Matthew Leckie finally saved the Socceroo's bacon with a goal four minutes before full-time.
For the Saudi Arabia players, the support of the massed ranks of their fans were key to ending their World Cup finals drought that begun after the 2006 edition.
But substitute Fahad Al-Muwallad's 63rd-minute goal capped off a frustrating night for Ange Postecoglou's men, who will have to do it the hard way to ensure a place at Russian Federation 2018.
Syria will now play in a two-legged play-off against Australia next month.
The Syrians are on a massive high after surprising Iran in Tehran.
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She says it was nothing like that and their lifestyle "was" never a problem. "Now they realize what a mistake that was". The Oscar victor added that a positive outlook is essential for getting through the tough moments in her life.
"I don't think I've ever shared a taxi with teammates (to the training ground), not even in my youth team days", defender Tomoaki Makino said in comments published by Kyodo news agency.
The Middle Eastern country has been torn apart by a brutal civil war which has lasted six years.
The performances may do little to win over sceptics, but Shin said fans have yet to see the real South Korea.
Syria, which has been playing its qualifiers in Malaysia because Federation Internationale de Football Association won't let it play at home because of the hostilities, has never come this close to qualifying before.
Under fire after being held 0-0 by 10-man Iran at home last week, they responded with another stalemate away to Uzbekistan on Tuesday.
Saudi football fans reacted to the kingdom qualifying for the next World Cup with praise and poetry for the young national team.
"We're in a hard situation, but we'll beef up our mental strength and will win", said Shin, whose side failed to create a single shot on target against Iran despite the visitors playing the last 40 minutes with 10 men.
After the final night of Asian qualifiers, South Korea and the Saudis joined Iran and Japan by sealing their trips to Russian Federation, while Syria and Australia finished third in their groups to go into the play-off series. Whichever side wins the play-off will meet either Costa Rica or Trinidad and Tobago or more probably Panama, United States or Honduras in an inter-confederation play-off.