BUSAN, South Korea (Kyodo)-- Koki Ogawa scored a hat trick in his international debut as Japan thumped Hong Kong 5-0 in the EAFF E-1 Football Championship final round on Saturday.
The 22-year-old striker staked his claim for Olympic selection as Japan easily accounted for Hong Kong, who lost 2-0 to hosts South Korea on Wednesday.
With only domestic players at his disposal, Japan manager Hajime Moriyasu capped a number of candidates for next year's Tokyo Games, where the men's tournament will be contested by under-23 teams including a limited number of overage players.
Ogawa -- on loan from Jubilo Iwata with second-division Mito Hollyhock -- was one of seven Samurai Blue debutants at Busan Gudeok Stadium.
Fellow first-timer Daiki Suga lashed home the opener in the eighth minute after an attempted clearance fell to him near the top left corner of the box.
FC Tokyo forward Kyosuke Tagawa added Japan's second from a set piece six minutes later, scoring with a glancing header off Ryota Oshima's corner kick.
Ogawa opened his account with an impressive strike in the 26th minute, receiving the ball with his back to goal, then turning and firing past Hong Kong keeper Tse Tak Him from the edge of the area.
He added Japan's fourth in first-half additional time, poking home from close range after multiple Hong Kong defenders failed to stop a short cross from Tagawa reaching him near the back post.
He brought up his hat trick with a header in the 58th minute, connecting with a deflected cross from Oshima directly in front of goal.
Japan, who beat China 2-1 in their opening match, will finish the round robin against reigning champions South Korea on Wednesday.