Henrique Capriles, a 40-year-old state governor, will face election favorite and acting President Nicolas Maduro. The pair must register their candidacies for the April 14 vote on Monday.
 

The election will decide whether Chavez's self-styled socialist and nationalist revolution will live on in the country with the world's largest proven oil reserves.
 

"I am going to fight," Capriles said at a news conference on Sunday. "Nicolas, I am not going to give you a free pass. You will have to beat me with votes."
 

Former Vice President Maduro, 50, a husky one-time bus driver and union leader turned politician who echoes Chavez's anti-imperialist rhetoric, is expected to win comfortably, according to two recent polls.
 

Maduro pushed for a snap election to cash in on a wave of empathy triggered by Chavez's death Tuesday at age 58 after a two-year battle with cancer. He was sworn in as acting president on Friday to the fury of Capriles.
 

"You have used the body of the president for political campaigning," Capriles said of Maduro on Saturday, triggering an angry rebuke.
 

Maduro accused Capriles of sowing hate.
 

"You wretched loser!" Maduro said of Capriles in a televised speech. "You have shown your true face — that of a fascist."
 

Capriles, the centrist Miranda state governor who often wears a baseball cap and tennis shoes, lost to Chavez in October. But he won 44 percent of the vote — the strongest showing by the opposition against Chavez.
 

Capriles has accused the government and Supreme Court of fraud for letting Maduro campaign without stepping down.
 

Opposition supporters were trying to raise their spirits despite the odds.
 

"There's no reason to think that the opposition is condemned to defeat," Teodoro Petkoff, an anti-government newspaper editor, said on his Sunday talk show.
 

Maduro has vowed to carry on where Chavez left off and ratify his policy platform. He acknowledged he has big shoes to fill.
 

"I am not Chavez — speaking strictly in terms of the intelligence, charisma, historical force, leadership capacity and spiritual grandeur of our comandante," he told a crowd on Saturday.
 

Chavez was immensely popular among Venezuela's poor for funneling vast oil wealth into social programs and handouts.
 

The heavy government spending and currency devaluations have contributed to annual inflation of more than 20 percent, hurting consumers.
 

"Maduro's success will depend on if he can fix the economy and its distortions," said a former high-level official in the Chavez government who declined to be named. "If he does that, he could emerge as a strong leader instead of one who is an heir."
 

Maduro's first official meeting on Saturday was with officials from China, whom Chavez courted to provide an alternative to investment that traditionally came from the United States.
 

He has adopted his mentor's touch for the theatrical, accusing imperialists, often a Chavez euphemism for the United States, of killing the charismatic but divisive leader by infecting him with cancer.
 

Emotional tributes were paid at a religious service at the military academy housing Chavez's casket on Sunday. Several million people have visited his coffin so far and his remains will be moved on Friday to a museum where a tomb is being built to show his embalmed corpse.
 

He may be moved later to another site next to the remains of his hero: 19th century liberator Simon Bolivar.
 

Chavez scared investors with nationalizations and railed against the wealthy. In heavily polarized Venezuela some well-to-do citizens toasted his death with champagne.

If elected, Capriles says he would copy Brazil's "modern left" model of economic and social policies.
 

Given the state resources at Maduro's disposal and the limited time for campaigning, Capriles faces an uphill battle.
 

"If the opposition runs, they'll lose. If they don't run, they lose even more!" tweeted Andres Izarra, who served as information minister under Chavez.
 

The opposition rank-and-file is heavily demoralized after losing last year's presidential race and getting hammered in gubernatorial elections in December, stoking internal party divisions.
 

"There's no doubt that it's an uphill race for Capriles," local political analyst Luis Vicente Leon said. "The trouble is that given the race is so close to Chavez's death, emotions get inflamed and the candidate probably continues to be Chavez rather than Maduro."