ROME (Reuters) -- Italian opposition leader Romano Prodi appeared to better Prime Minister Silvio Berlusconi in a head-to-head television debate on Tuesday, but failed to land a knockout blow four weeks before an April 9-10 general election.

Berlusconi, who is trailing in the opinion polls, admitted at the end of the 1-1/2 hour confrontation that he had failed to get his message across, while a smiling Prodi said he was "very happy" with the outcome.

A snap survey by the Piepoli pollsters said 38 percent of viewers thought Prodi had won the encounter against 35 percent who put Berlusconi ahead. Some 27 percent said it was a draw.

Berlusconi, who prides himself on his communication skills, repeatedly accused his center-left opponent of distorting the truth and giving "shameless" answers.

But Prodi, a former president of the European Commission, withstood the pressure and launched his own fierce attacks on Berlusconi, accusing him of having wasted his five years in government and dividing the nation.

Mario Morcellini, a communications professor at Rome university, said he thought Prodi won the day.

"It was incredible to see how bad Berlusconi was in the way he used the camera, the way he got muddled up and had to correct himself on several occasions," he said.

Prodi's center-left bloc has a lead of around 4 percentage points over Berlusconi, according to latest opinion polls, but a recent survey showed that nearly a quarter of voters remained undecided meaning the result could yet go either way.

Previous television debates in Italy have taken place in an "anything goes" atmosphere but Tuesday's encounter was rigidly stage-managed, held in a bland television studio and using rules laid down for recent U.S. presidential debates.

Berlusconi regularly overran his time limit and at the end expressed frustration with the restrictions.

"It seems to me we have not succeeded, at least as far as I am concerned, to give Italians what they wanted to know," said Berlusconi in a rare admission of failure for a man famed for his upbeat optimism and can-do attitude.

Prodi, seeking to shake off his image as a grey politician, regularly smiled and looked directly at the camera, urging voters to give him a chance to revive the stagnant economy.

"This is where you need someone who in a strong, disinterested manner gives back this sense of unity, this hope to new generations, who can make people understand that Italy is a great country," he said.

Berlusconi repeatedly ridiculed Prodi's answers. "I can't believe my ears and eyes," he said, wearily shaking his head.

He then accused his opponent of being just a "front man ... a facade" for his broad alliance, which stretches from Roman Catholic centrists to Communists.

Prodi snapped back that he wanted more respect and then turned on Berlusconi for often harking back to problems he had inherited when he took power in 2001. "You talk as though you had been in opposition (since 2001). In these five years with a 120 seat parliamentary majority, what have you done? Approved laws that only concerned yourself?"

Much of the debate was dominated by questions over the economy, with the two men explaining their tax policies and trading accusations over who was to blame for a surge in prices when euro coins and notes were introduced in 2002.

Vincenzo Guzzo, an economist with Morgan Stanley, said he was unconvinced by their proposals to revive the economy, which grew by an average annual 0.6 percent over the past five years.

"I was a bit disappointed by the debate. It seems to me that both men are still looking too much at the past ... rather than providing convincing proposals for the future," Guzzo said.

Berlusconi and Prodi are due to hold a second and final televised debate on April 3. "I've taken notes. It doesn't end here," the prime minister said at the end of the debate. -- Additional reporting by Francesca Piscioneri, Gavin Jones and Robin Pomeroy.