It was their last chance to make the case on the debate stage and convince New Yorkers they've got what it takes lead the city, and battle lines were drawn early.
Brooklyn Borough President Eric Adams, the current frontrunner according to polls, was the target of attacks but rarely unleashed his own, employing a similar tactic to previous debates, choosing to wait to be the subject of specific attacks before targeting his opponents.
Adams was a target, as former presidential candidate Andrew Yang, who has tumbled to fourth place in the latest polls, trained his fire on him early and often.
"The people you should ask about this are Eric's former colleagues in the captain's union," Yang said in response to a question about why he would be a better candidate for public safety. "People who worked with him for years, who know him best, just endorsed me for mayor of New York City. They think that I'm a better option to keep us and our families safe."
City Comptroller Scott Stringer was also on the attack, mostly focusing his attention on Yang, using every opportunity to question Yang's knowledge of city government — a frequent criticism of Yang, who has never held public office.
"That is the greatest non-answer I've ever heard. Not one specific idea, not one specific plan. You started out with hotels, now you're into psych beds, how much is that going to cost?" Stringer said in response to Yang, who said he would expand the number of mental health beds available across the city.
Candidates were asked what they thought were some of the worst ideas from their opponents, which resulted in yet another exchange between Yang and Adams.
"Eric Adams' advice to bring a fire arm as a public safety measure, I think it speaks for itself," Yang said.
Adams fired back, criticizing Yang's signature policy of universal basic income.
"UBI, then it went to borough bucks and monopoly money to hopes and prayers. We have to have real solutions," Adams said.
The question also prompted a testy exchange between Adams and Maya Wiley, who criticized Adams for his plan to bring back the NYPD's anti-crime unit and a version of the controversial tactic known as stop-and-frisk.
"The worst idea I've heard is bringing back stop-and-frisk and the anti-crime unit from Eric Adams," Wiley said.
Adams responded by highlighting Wiley's family decision to pay for private security in their neighborhood, noting it's not something a majority of New Yorkers have access to in order to feel safer.
"You don't have to worry about danger when you have private security on your block," Adams said.
Ray McGuire, the former Citigroup executive, was looking to define himself from the bunch. He accused his opponents of resorting to tag lines and was critical of some candidates' support for defunding the police, but it resulted in a retort from Dianne Morales.
"You don't speak for Black and brown communities,” Morales said. “How dare you assume to speak for Black and brown communities as a monolith.”
Morales is the only candidate to fully adopt the language of the defund movement and has committed to cutting $3 billion from the NYPD.
There was substantive discussion about the city's public schools, housing and what to do about the mental health crisis. Some candidates said they're supportive of forcing those who are mentally ill into treatment.
Former sanitation commissioner Kathryn Garcia, who has been surging to the top in the most recent polls, was on the hot seat, having to answer about her inability to cut the sanitation budget at a time of crisis.
"I have confronted budgets before. When I was at the Department of Environmental Protection I cut $100 million out of the operating budget," Garcia said.
Garcia has been rising in the polls, but her frontrunner status was not widely reflected at the debate: her opponents rarely attacked her, perhaps hoping she stays many voters' second choice.