Yoshihiko Noda's victory against Banri Kaieda in the Democratic Party of Japan presidential runoff Monday dealt yet another blow to disgraced kingpin Ichiro Ozawa, who backed Kaieda in an apparent bid to boost his waning influence.

Kaieda's defeat and Noda's subsequent installation as prime minister Tuesday effectively scotched any effort by Ozawa to retain his role as the behind-the-scenes power broker and "shadow shogun," and may symbolize a step away from a DPJ leadership long dominated by the "troika" of Ozawa, former Prime Minister Yukio Hatoyama and Noda's predecessor, Naoto Kan.

Monday's race was the third party presidential election since the DPJ came to power in 2009 that Ozawa has failed to work to his advantage, leading some pundits to conclude the veteran lawmaker's time at the forefront of politics may be near an end.