Leftist candidate Roberto Sanchez has advanced to a presidential runoff against conservative frontrunner Keiko Fujimori following a highly contested election.Markets reacted negatively to the prospect of Sanchez replacing the central bank governor, causing the Lima Stock Exchange to drop four percent as the central bank moved to protect the currency.Amid ongoing demands for an annulment from a trailing candidate, both frontrunners are preparing for a critical final vote to decide the future of the nation.