Japan crashed to its first defeat of 2009 after a 1-0 loss away to Bahrain in the final round of qualifiers for the 2011 Asian Cup on Wednesday night.
Salman Issa struck the decisive blow in the 24th minute at Manama's National Stadium as Bahrain made it two wins out of two in Group A after last week's 3-1 win over Hong Kong.
Japan, 2-1 winners over Yemen in its opening game, are level on three points with the Yemenis, who beat Hong Kong 1-0 earlier in the day.
Japan coach Takeshi Okada, who described defeat here nearly a year ago in a World Cup qualifier as the most humiliating moment of his career, admitted his side had been second best and was unhappy about the manner in which his players repeatedly conceded possession in the middle of the park.