The public advocate reiterated his campaign promise to bring fresh leadership to City Hall in an effort to fend off his attackers during the 90-minute debate hosted by various local media inside NBC's Rockefeller Center studios Tuesday night.
"You're not going to solve big problems in this city with small ideas," de Blasio said. "We need bold ideas if we are going to make change."
But rivals, spurred by a Quinnipiac poll released hours before the debate that put de Blasio's support at 43 percent of those polled, said his "bold ideas" ignored the harsh realities of New York politics.
"A bold proposal isn't about putting forward something that's never going to happen," Thompson said.
The former Democratic front-runner and City Council Speaker Christine Quinn blasted the public advocate over reports that he accepted campaign contributions from property owners who had been featured on his list of notoriously bad landlords.
"It's Bill talking out of both sides of his mouth, making a list that's supposed to help tenants but really it ended up becoming a campaign fundraising list for the public advocate," Quinn said.
During the debate — in which Quinn tried to overcome her abrasive reputation by softening her tone and projecting warmth — she also called out de Blasio for his inconsistency, citing his support of extending term-limits in 2005 and his about-face on the issue in 2009.
One of the debate's moderators, The Wall Street Journal's Michael Howard Saul, asked de Blasio, "Did you flip on term limits? Yes or no?"
"I made abundantly clear that what the mayor did in 2008 was wrong, and I led the opposition against it. Period," de Blasio replied.
A candidate needs to win 40 percent of the vote in the Democratic primary on Tuesday, Sept. 10, in order to avoid a run-off election.