The Socceroos' emphatic win in Doha came hours after Oman had caused a major upset edging past Japan 1-0 in Suita while South Korea were held to a goalless draw by a plucky Iraq side in Seoul.
Covid restrictions made it impossible for Australia to play their opening match in Sydney, but they still started their Group B campaign in style at the Khalifa International Stadium, one of the venues for next year's event in Qatar.
There are two groups of six nations in the final round of Asian qualifiers for the Qatar World Cup.
The top two teams from each group will qualify for the tournament next year while the third placed teams can still hope to make the cut via an inter-continental playoff.
Kenya-born Awer Mabil put Australia ahead in the 24th minute. China goalkeeper Yan Junling foiled his first effort but Adam Taggart retrieved the ball and set up Mabil for a second chance.
The Chinese hardly had time to recover as Martin Boyle struck two minutes later with an immaculate shot from 20 yards after latching onto a pass from Tom Rogic.
China struggled to get a decent shot on goal while the Aussies wasted chances galore with Mabil, Boyle and Taggart among those missing out.
A third goal looked inevitable and it came in the 70th minute with Mitch Duke making no mistake with an easy poke after Yan parried the ball in his direction while stopping another Mabil effort.
Earlier, Oman upset Japan thanks to an Issam al-Sabhi goal in the closing minutes.
Japan's shock home defeat in Group B came after the Samurai Blue dominated the earlier qualifying rounds, winning eight out of eight.
After a scoreless first half at a rainy Panasonic Stadium in Osaka, the hosts sent on young stars Takefusa Kubo and Ritsu Doan - both joining the national team after playing in the Tokyo Olympics.
But Oman broke through Japan's defense several times and Al Sabhi netted the 88th-minute winner - just a few minutes after coming off the bench.
He said it was an "amazing feeling" when he scored the goal.
'Really bad' Japan
"Thank God. We got a good result. We worked together very hard," he told a news conference.
Japanese captain Maya Yoshida lamented the team's showing.
"We lost as we were supposed to lose," he said.
"Our tempo was bad. Our combination was bad. Really bad."
Elsewhere, Vietnam surprised Saudi Arabia with a third minute goal by Nguyen Quang Hai in Riyadh but the hosts bounced back with three second-half strikes to clinch a 3-1 win.
Salem al-Dawsari and Saleh al-Shehri scored from penalties and Yasser al-Shahrani also struck a goal as the Saudis grabbed three points.
Saudi Arabia's Gulf neighbours UAE were held to a goalless draw by Lebanon in Dubai.
Meanwhile, Iraq held South Korea to a 0-0 draw in Seoul while Iran edged Syria 1-0 as the two regional rivals impressed in their opening Group A games.
Iraq played with more attacking intent in the second half, but never posed a real threat. They did however succeed in nullifying the hosts' attackers, particularly captain Son Heung-Min.
"The outcome is very hard to accept," a visibly upset Son said after the game, which was held without fans because of coronavirus restrictions.
Iran, traditionally slow starters, pipped Syria with captain Alireza Jahanbakhsh scoring off an excellent Mehdi Taremi assist in the 56th minute at the Azadi Stadium in Tehran.
But there was an element of luck involved in the goal as Jahanbakhsh's shot took a huge deflection from Syria's Thaer Krouma before finding the net.
Standout matches today