Jakarta , Indonesia ( CNN ) -- Indonesia 's presidential candidate , Prabowo Subianto , who slammed the country 's election commission and rejected the official results of the vote held earlier this month , appears poised to launch a legal challenge . A member of Prabowo 's legal team said they plan to file a complaint against the election commission at the Constitutional Court on Friday . The court has until August 21 to make a ruling . His opponent , Joko `` Jokowi '' Widodo , won Indonesia 's presidential race with 53 % of the votes over Prabowo 's 47 % , the country 's election commission announced on Tuesday . Hours before the release of the voting results from ballots cast on July 9 , Prabowo criticized the election commission , citing what he called `` massive , structural and systematic cheating . '' In his speech carried live , he declared : `` We withdraw ourselves from the process . '' His statement drew confusion and uncertainty . But on Wednesday , his brother and business tycoon Hashim Djojohadikusumo said , `` Let me be clear , Prabowo never withdrew as a candidate for president . '' He said they would have accepted the results , whether the former lieutenant-general won or not , if they believed the vote count was fair . `` We continue to have grave concerns about the integrity of the electoral process in a number of provinces , '' his brother said . `` An estimated 52,000 polling stations have reported irregularities , putting an estimated 21 million votes in question . The indication of massive fraud and widespread irregularities is overwhelming . '' Congratulations for Jokowi . Meanwhile , congratulations from the United States , Singapore , Malaysia and other nations poured in for Indonesia 's president-elect . Widely known as `` Jokowi , '' he has drawn comparisons to Barack Obama for his unlikely ascent , from growing up in humble origins to becoming a national politician . On Tuesday , he delivered a speech aboard a traditional Indonesian boat , calling for national unity in the world 's most populous Muslim nation . `` I ask you to heal your relations within your family , with neighbor to neighbor and with friends that were once broken . '' The new president will be inaugurated on October 20 . CNN 's Kathy Quiano reported from Jakarta , Indonesia and Madison Park wrote from Hong Kong . CNN 's Jason Hanna contributed to this report .
Candidate Prabowo Subianto criticizes country 's election commission . Election commission : Joko `` Jokowi '' Widodo won election with 53 % of votes . Prabowo 's team to file legal challenge by Friday .