Marcus Douthit scored 25 points to lead the Philippines to an 83-76 win over Japan in the FIBA Asia Championship's eight-final round on Tuesday in Wuhan, China.
Japan, coming off a 101-61 win over the United Arab Emirates on Monday, fell to 4-1 in the tournament.
Joji Takeuchi had a team-high 22 points and eight rebounds for Japan, while Takeki Shonaka scored 14 points, Kenta Hirose added 13 and Takuya Kawamura had 12.
The Philippines outscored Japan 26-12 in the pivotal third quarter and took a 60-52 lead into the fourth quarter.
Japan shot 12-for-33 from 3-point range. The Philippines held a 44-31 edge in rebounds.
On Wednesday, Japan faces host China.