Former U.S. President Bill Clinton defended President Barack Obama's handling of the U.S. economy Wednesday night, in support of the latter's re-election campaign.

U.S. President Barack Obama (L) and former U.S. President Bill Clinton wave to the participants during the Democratic National Convention in Charlotte Sept. 5, 2012. U.S. Democrats nominated Obama to lead the party's presidential ticket during a roll call vote running through late Wednesday night to early Thursday. [Zhang Jun/Xinhua]

Clinton delivered the much-anticipated address on the second day of the Democratic National Convention here in North Carolina's largest city.

He launched a counter-attack against the Republicans' frequent criticism of Obama over the country's economic woes, saying it was unfair to pin the blame on Obama for the economic ills he inherited four years ago.

"No president, not me, not any of my predecessors, could have fully repaired all the damage that he found in just four years," Clinton said.

Noting that many Americans were still "frustrated" by the current fragile economy, he suggested "too many people do not feel it yet" and more time was needed for pro-growth measures to take effect.

The former president also tried to sharpen the contrast between the Democrats' and Republicans' visions for the country.

"If you want a winner-take-all, you're-on-your-own society, you should support the Republican ticket," Clinton said. "If you want a country of shared prosperity and shared responsibility, a we're-all-in-this-together society, you should vote for Barack Obama and Joe Biden."

Clinton touted Obama's efforts across the board, including health-care reform, education, job creation and economic recovery, issues bearing most of the Republicans' attacks during the election year.

The veteran politician's speech formally made Obama the party's nomination for a second term.

Twelve years after leaving office, Clinton still holds the political limelight and has appeared several times at Obama's fund-raising events this year and starred in campaign ads.

Clinton told NBC News earlier in the day he hoped his speech would give a boost to Obama's re-election bid.

His wife, Hillary, is legally barred from political activities while serving as the Obama administration's secretary of state.

The latest Pew poll shows about 40 percent of Americans are following what happens at the Democratic National Convention in Charlotte, down from the 59 percent four years ago, when Obama accepted the party's presidential nomination for the first time.

There is a slim chance for Obama to rekindle voters' enthusiasm with a "forward" agenda, as he did four years ago chanting "hope" and "change."

Surveys show the incumbent and the Republican challenger, Mitt Romney, are still deadlocked nationally on voter support. However, a recent Washington Post-ABC News poll showed Obama continued to receive more negative reviews than positive ones for his handling of the economy.