Keisuke Honda's appearance as a second-half substitute paid dividends as Japan eased past Guatemala 3-0 in a friendly in Osaka.
The CSKA Moscow midfielder stepped off the bench at half-time, heading home the opening goal just five minutes later.
Masato Kudo made it 2-0 in the 69th minute, with a free-kick from Yasuhito Endo seven minutes later making sure of the win.
Two goals from Yu Dabao set China on their way to a 6-1 demolition of Singapore in Tianjin.
The Dalian Aerbin forward opened the scoring after eight minutes, and although that goal was cancelled out by Shahfiq Ghani nine minutes later, Yu struck again on the half hour to restore China's advantage.
The hosts then scored twice more before the interval, a penalty from Zhang Xizhe and a goal for Sun Ke, to take a firm grasp on the match before Zheng Long's late double completed the rout.
South Korea were also comfortable winners in their friendly, beating Haiti 4-1.
The home side led through Son Heung-min's drive from distance after 21 minutes, although Kervens Belfort ensured the scores were level at half-time.
But second-half penalties from Koo Ja-cheol and Lee Keun-ho gave South Korea the advantage before Son grabbed his second of the match 17 minutes from time.