Venezuelan President Hugo Chavez and his opponents rallied their supporters on Thursday in last-ditch campaigning before a referendum on Sunday that could eject the left-wing populist or keep him in office until 2006 elections. From Venezuela's poor slums and hamlets to the wealthy residential enclaves of Caracas and other cities, voters were expectantly awaiting what many see as the most important election held by the world's No. 5 oil exporter in decades. At a news conference broadcast from the presidential palace, a breezily confident Chavez described victory on Sunday as "inevitable." "We have such an advantage over the opposition that any surprise is impossible," he said. Buoyed by an energetic campaign that has lifted his chances of staying in power, the president planned a rally later near the palace. His opponents were gathering in east Caracas in the last formal campaign events permitted before Sunday's poll. The vote will be a contest between an extrovert president hailed by followers as a Latin American nationalist and champion of the poor and opponents who revile him as a dangerous autocrat leading the country to ruin. --MORE 2112 Local Time 1812 GMT