Lori Lightfoot on Thursday claimed endorsements from the Chicago Firefighters Union — and from two aldermen who once served as firefighters — with potential to help her win Northwest and Southwest Side wards that Jerry Joyce carried on Feb. 26.

Local 2 President Jim Tracy sang Lightfoot’s praises with Aldermen Nick Sposato (38th) and Anthony Napolitano (41st) at his side as Lightfoot released her first negative TV commercial of the runoff campaign and showcased an internal poll that shows her headed for a landslide victory on April 2.

The endorsement from the union representing firefighters and paramedics could help Lightfoot in the 19th and 41st Wards, where many firefighters live.

Joyce won both vote-rich wards. His home 19th Ward led the city with a 55.8 percent turnout. Joyce came out of that ward with 9,098 votes, compared to 2,087 for Bill Daley, 1,947 for Paul Vallas, 1,702 for Lighftoot and 1,629 for Toni Preckwinkle.

In the 41st Ward, turnout was 46.8 percent. Joyce got 3,530 votes to 3,182 votes for Daley. Lightfoot had 1,463 votes, nearly twice as many as Preckwinkle.

“She understands Local 2’s needs, when it comes to our staffing, antiquated rigs and the need for more ambulances,” Tracy told a news conference at a South Side firehouse.

Tracy said he discussed “a lot of stuff” with Lightfoot before deciding to endorse her.

“Staffing’s our big thing. Rigs are a big thing. EMS. We put five ambulances in and it was not putting a hole in the dike. We need a lot more. We need more resources,” he said.

Without mentioning Preckwinkle by name, Tracy said, “Her opponent is a very nice woman and she’s done some good things. But, we feel that Lori is the person who’s gonna bring Local 2 and the city of Chicago forward.”

With Sposato and Napolitano standing nearby, Lightfoot said she was “humbled” by the endorsement of a union whose members are “part of the fabric” of Chicago neighborhoods.

Last year, Sposato accused Lightfoot of committing the “ultimate act of betrayal” by using the political platform Mayor Rahm Emanuel gave her as Police Board president to hammer him and attempt to take his job.

“We need to make sure we’re doing everything we can to provide them with the support and resources they need,” she said.

“We’ve had a lot of great conversations over the last couple of days about some of the specific issues that are relevant to firemen and women and EMS. And I’m gonna make sure that, as mayor, we meet those challenges and meet those needs.”

Like rank-and-file Chicago Police officers, firefighters and paramedics have been working on an expired contract since June 30, 2017.

Last summer, Mayor Rahm Emanuel finally moved to deliver on that contract’s four-year-old promise to add five ambulances to reduce dangerously high response times under pressure from Vallas.

In 2011, Local 2 backed Gery Chico over Emanuel. Four years later, the firefighters union endorsed Jesus “Chuy” Garcia.

After finishing a surprising second on Feb. 26, Preckwinkle came out smoking with a commercial that sought to portray Lightfoot as a “wealthy corporate lawyer who’s defended the elites in this country” only to “recast” herself as a police reformer despite a record showing otherwise.

On Thursday, Lightfoot pushed back with a vengeance.

“Why is Toni Preckwinkle launching a ‘full blown,’ and ‘incorrect’ attack against Lori Lightfoot?” the narrator asks.

The ad then shows a series of newspaper headlines and television newscasts outlining Preckwinkle’s ties to embattled Ald. Edward Burke (14th), her decision to hire Burke’s son for a sensitive county Homeland Security job, and about Preckwinkle’s wildly-unpopular and now-repealed tax on sweetened beverages.

“An entrenched political insider won’t lead Chicago forward. It’s time to bring in the light,” the announcer says over footage of Lightfoot’s election night celebration.

Burke, former longtime chairman of the City Council’s Finance Committee, was charged Jan. 3 with attempted extortion for allegedly shaking down a Burger King franchise owner for legal business and for a $10,000 contribution to Preckwinkle’s re-election campaign as county board president.

Preckwinkle did not report the contribution until after Burke was charged. She has since returned all $116,000 she raised during a January 2018 fundraiser at Burke’s Gage Park home.

Lightfoot’s internal poll of 799 likely voters was conducted by her own pollster, Jason McGrath, from Feb. 28 through March 3. It shows her headed toward a landslide victory with 59 percent of those surveyed to Preckwinkle’s 29 percent. The poll has a margin of error of plus or minus 3.5 percentage points.

A Preckwinkle strategist, who asked to remain anonymous, took the results in stride, arguing that you “can’t poll immediately following an election.”

Lightfoot “got a bump,” but it isn’t 20 or 30 points,” the Preckwinkle strategist said.

“The polls will all settle down in a week or 10 days. Then, we will see what the race really looks like,” the Preckwinkle strategist said.

“Her numbers are soft and once voters hear who she is, they move. Lori just went negative on TV. That isn’t what you do if you are super confident in your poll numbers.”

As for the firefighters union, the Preckwinkle strategist said: “Endorsements aren’t going to decide this election. The voters will.”