Syrian fans expressed joy as their fairytale World Cup campaign headed into an Asian play-off against Australia -- whose coach found himself under rising pressure.

Saudi Arabia also celebrated booking their spot at Russia 2018, but South Korean supporters appeared unconvinced after a 0-0 draw with Uzbekistan took their team to a ninth straight World Cup.

After the final night of Asian qualifiers, South Korea and the Saudis joined Iran and Japan by sealing their trips to Russia, while Syria and Australia finished third in their groups to go into the play-off series.

Syria's Omar Al Soma scored in injury time to force a 2-2 draw at Iran's Azadi Stadium, earning a crucial point that set off celebrations in their war-ravaged homeland.

Syria have never reached the World Cup before, and their current success comes despite the brutal civil war that has forced them to play all their home games abroad.

"I cannot describe my happiness... I hope that peace will prevail across Syria," said Lara Hanna, 35, who watched the game in a Damascus coffee shop.

"Of course we wanted the national team to win," even if Syria is divided into "the opposition and the regime", said 30-year-old Abu Badr in Eastern Ghouta, where a group of fans watched the game in a farm.

"The team represents all of Syria and we hope they will win in the play-offs and go on to qualify for the World Cup," he said.

The mood was markedly worse in Australia, where the Socceroos were pitched into the lottery of the play-offs despite a 2-1 victory over Thailand in Melbourne.

Coach Ange Postecoglou, who led Australia to the Asian Cup title in 2015, brushed off questions about his future while admitting he was "not everyone's cup of tea". 

"What do you do? I took the role to do it a certain way and I'll see it through," Postecoglou said.

"I've survived much worse than this and if anything it motivates me to keep going because I want to make sure Australian football gets on the right path."

- 'Lippi loves China' -

China, bidding to improve on their world ranking of 77th and become one of the globe's top football nations, again missed out despite their 2-1 win over Qatar, the 2022 World Cup hosts.

But China's fortunes have risen since the arrival of Marcello Lippi last October, and officials praised the achievements of the Italian World Cup-winning coach.

"Since Marcello Lippi has been leading the team, the changes have been very big," said Chinese Football Association (CFA) president Cai Zhenhua, according to the People's Daily.

"The team has an entirely new aspect," he added. "Marcello Lippi loves China very much. We also hope that he can offer his football philosophy and rich experience to China."

South Korea's coach Shin Tae-Yong also took over mid-campaign, and he promised doubtful fans that the team would be much improved by Russia.

The Taeguk Warriors suffered shock qualifying defeats to China and Qatar, and ended their campaign with back-to-back goalless draws. 

"The world will see how strong South Korea are at the World Cup," he told journalists after Tuesday's stalemate in Tashkent.

South Korea's fans, however, feared the worst.

"Should we go to the World Cup just to be knocked out in the first round?" posted one fan, while another wrote: "I am confused. Why am I angry rather than joyful after the team reached the World Cup?"

Syria and Australia play a two-legged play-off next month, with the winner going into an intercontinental play-off against a team from the CONCACAF federation.