Gone is the Mr. Rogers sweater and out are the brass knuckles.

Chicago Mayor Rahm Emanuel has dropped the nice guy pose and has unleashed a blistering attack on his opponent, Jesus “Chuy” Garcia.

Just three days ago, Emanuel was featured in an ad attempting to boost his nicer, gentler image.

“They say your greatest strength is also your greatest weakness. I’m living proof of that. I can rub people the wrong way or talk when I should listen. I own that,” Emanuel says. “But I’m driven to make a difference. When politics stood in the way of a full-day kindergarten or tougher gun laws, I charged ahead. And when business interests said a $13 minimum wage was too high, I didn’t back down.

“Look, I’m not going to always get it right. But when it comes to fighting for Chicago and Chicago’s future, no one’s going to fight harder.”

They must have run out of time for him to toss his sneaker from one hand to the other.

Now, with the polls sagging, it’s desperation time.

A new Emanuel campaign ad is a full frontal assault on Garcia, which the Chicago Tribune says “takes liberties” with his opponent’s positions.

It begins by claiming Garcia has “made $1.9 billion in spending promises,” and asserts that amounts to “$1,900 in additional taxes for the average homeowner.”

The ad also states Garcia’s only option to pay for it all is “creative sources of financing.”

It ends: “Creative sources of financing? Uh-oh.”

“What this demonstrates is that Rahm Emanuel took the fuzzy sweater off again … and now we’re seeing the real Rahm,” Garcia says in response to the ad.

“The Rahm that will attack to distract, the Rahm that can’t offer a financial plan himself, and the Rahm that has demonstrated that he cannot manage the city’s finances adequately.”

 Recent polling indicates the race between Emanuel and Garcia is “dead even.”