BRASILIA, June 23 (Reuters) - Brazil"s Supreme Court on Wednesday confirmed its earlier ruling that a lower court judge had failed to treat ex-President Luiz Inacio Lula da Silva fairly in graft probes, a decision that could lead other cases against the left-wing leader to be thrown out. With a vote of 7 to 4, the high court upheld the decision that former judge Sergio Moro was biased against Lula, throwing out a corruption conviction against the former president. Lula"s defense team has already requested that the Supreme Court evaluate whether other cases against Lula that were judged by Moro should be thrown out. In April, the Supreme Court also tossed out other graft convictions against Lula, ruling that the court where they were tried lacked jurisdiction. A poll conducted last month predicted that Lula would beat right-wing President Jair Bolsonaro in a run-off vote if the 2022 election were held today. (This story corrects spelling of Lula"s name in first paragraph)