With a potent left, Danny Garcia capped a historic night for boxing in Brooklyn.

Garcia, 24, remained undefeated and kept his unified super lightweight world championship with a powerful punch that spun Erik Morales down and into the lower rope at 1:23 of the fourth round at Barclays Center Saturday night.

Morales, 36, was allowed to fight in the historic card at the $1 billion home of the Nets -- the first major championship title event in 81 years in the borough -- despite two tests earlier this month that found minor traces of clenbuteral, a banned weight-loss drug. A third test, taken Wednesday, came back negative. Morales said he had eaten contaminated food and the New York State Athletic Commission said Saturday that there was "inconclusive data to make a final determination on a suspension" and would continue investigating.

Garcia, a Philadelphian who is 25-0 with 16 knockouts, beat Morales in a unanimous decision in March for the WBC light welterweight title and won the WBA light welterweight title with a fourth-round TKO of Amir Khan in July. "I was more aggressive this time [against Morales],'' Garcia said. "I don't duck anybody. I fought Khan when nobody gave me a chance. Line 'em up and I'll knock em down. My dad called it in the fifth. Well, it was the fourth.''

So the borough officially came back on the boxing map -- in more ways than one -- with all the local talent on the bill winning before a crowd of 11,112.

Brooklyn favorite Paulie Malignaggi (32-4, seven knockouts) kept his WBA welterweight world championship belt against Pablo Cesar Cano (25-2-1, 19 KOs). Cano, 22, technically wasn't eligible to win the crown; he weighed in above the 147-pound limit. Cano landed a right to send Malignaggi down in the 11th, but the judges gave the bout to the hometowner in a split decision. He won, 114-113, on two cards; Cano had the other, 118-109.

Cano did land more power punches -- 65 to 57 -- and 35 percent of punches thrown, compared to Malignaggi's 26 percent, and his team wasn't happy.

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Just before that, Manhattan's Peter Quillin won his 28th straight fight, a thriller, in a unanimous decision and took the WBO middleweight world championship belt from the previously undefeated Hassan N'Dam, who was knocked down six times in the 12-rounder. All three judges scored it 115-107.

In the first championship bout in the borough since Aug. 5, 1931, when "Slapsie Maxie" Rosenbloom retained the New York world lightweight title at Ebbets Field with a decision over Jimmy Slattery, Devon Alexander (24-1) took Randall Bailey's IBF welterweight crown with flurries of jabs in a unanimous 12-round decision. It was only the second fight as a welterweight for Alexander, 25, who hails from St. Louis.

Perhaps the most impressive display on the undercard was by middleweight Danny Jacobs, a 25-year-old Brownsville native who was paralyzed by cancer in his back in 2011 and was making his comeback against Josh Luteran. Jacobs unleashed a left-right combination at 1:13 of the opening round to floor Luteran and move to 23-1.