Japan's Ayase Ueda scored a hat-trick as a largely second-string side defeated Myanmar 5-0 after Hajime Moriyasu chose to leave many of his leading performers on the bench ahead of their more exacting Group B clash with Syria in Jeddah on Tuesday.
Ueda put the Japanese ahead in the 11th minute at Suita Stadium outside Osaka when he headed in Takumi Minamino's lofted pass and Daichi Kamada doubled the advantage 17 minutes later from distance.
Ritsu Doan's angled through ball set up Ueda to claim his second in first-half injury time with a neat first-time finish and he completed his hat trick five minutes into the second half after another Minamino dink unlocked the Myanmar defence.
Doan scored the fifth four minutes from time with a cool finish as the Japanese made light work of their visitors.
Australia were also untroubled as they completed a 7-0 demolition of Bangladesh in Group I with Jamie Maclaren stepping off the bench to score a second-half hat-trick.
Mitchell Duke hit a brace late in the first half as Australia trampled over the 183rd-ranked South Asians at Melbourne Rectangular Stadium.
Goals from Harry Souttar and Brandon Borrello had given the hosts a two-goal lead inside the first 20 minutes while Duke then scored twice in four minutes, nodding in a header from Metcalfe's assist before firing in a rebound off the post.
Maclaren did all the damage in the second half, scoring from a Jordan Bos cross shortly after the restart before pouncing again in the 70th when a Massimo Luongo shot pinged off goalkeeper Mitul Marma.
Lewis Miller then set up Maclaren's hat-trick goal in the 84th minute with another neat cross.
The South Koreans, meanwhile, scored four times in the second half to hand Singapore a 5-0 defeat at Seoul World Cup Stadium, with captain Son Heung-min among the scorers.
Cho Gue-sung put Jurgen Klinsmann's team in front a minute before the halftime break and Hwang Hee-chan added the second four minutes into the second half.
Son hit the third in the 63rd minute before Hwang Ui-jo's penalty and Lee Kang-in's late effort confirmed the victory for the Koreans in Group C.
The Koreans have been joined on three points by China, who beat Thailand 2-1 in Bangkok with Wang Shangyuan hitting the decider 16 minutes from time.
Iran top Group E after Sardar Azmoun's early double helped them on the way to a 4-0 win over Hong Kong. They are joined on three points by Uzbekistan, who beat Turkmenistan 3-1.
Saleh Al Shehri scored twice as Saudi Arabia won 4-0 against Pakistan in Group G, with injury-time goals from Abdulrahman Ghareeb and Abdullah Radif enhancing the scoreline while Jordan were held to a 1-1 draw by Tajikistan.
Malaysia notched up a 4-3 win over Kyrgyzstan in Group D where Oman also prevailed, securing a 3-0 win over Taiwan.
Vietnam defeated hosts the Philippines 2-0 in Group F before Iraq secured a comfortable 5-1 victory over Indonesia while in Group H the United Arab Emirates eased to a 4-0 win over Nepal.
Almoez Ali netted four times in Qatar's 8-1 Group A demolition of Afghanistan and India had Manvir Singh's 75th-minute strike to thank for their 1-0 win over Kuwait.
North Korea played their first senior international in four years on Thursday and they lost 1-0 to Syria in Jeddah in one of the last ties of the round.
In the 36th minute, Omar Al Somah scored a penalty after North Korea's goalkeeper, Kang Ju-hyok, collided with him.
Bahrain claimed a 2-0 victory against Yemen, with Mohamed Marhoon scoring the opener, followed by Yemen defender Harwan Al Zubaidi conceding an own goal in the first minutes after the break.
