"We were up against not only Mendy Mirocznik but every elected official in the party and the entire Democratic machine," Mancuso said at his celebration, the Staten Island Advance reported. "We did it."
Mancuso, an auxiliary police officer and former small business owner, received 2,864 votes, while Mirocznik received 1,911.
Mancuso previously told DNAinfo New York that if elected, his priority would be getting Hurricane Sandy victims back in their homes and to work on better protection for shorefront neighborhoods.
"The berms that they built aren't going to do much, they're going to be washed away,” he said. "I could've given 100 kindergartners plastic shovels and they could have built a better berm."
Mancuso will square off against Republican Matteo for the 50th Council seat in November.
Matteo, who had a fiery campaign against Lisa Giovinazzo for the Republican spot, came out on top with 54.6 percent of the vote, according to the Times.
In his speech, Matteo vowed to unite the Staten Island GOP party after the fierce race, the Advance reported.
"We're going to unite this party," he said. "We're going to win in November."
Matteo, chief of staff for outgoing Councilman James Oddo, also said his No. 1 priority would be Sandy victims, and said he would work on a redevelopment plan to buy out homeowners in hard-hit areas, but give them the option to return if new, safer homes are built.
“Hurricane Sandy devastated many communities in the district and its effects continue to be felt,” he told DNAinfo New York.
“We have a responsibility and obligation to help make these communities whole again, and to ensure their future safety and security.”
Matteo received 2,822 votes, while Giovinazzo got 2,344.