Sergio Martinez retained his world middleweight title with a TKO after Matthew Macklin couldn't answer the bell for the 12th round in a souldout fight at The Theater at Madison Square Garden. It was Martinez's fourth defense of his title, with each victory coming by way of knockout.

Macklin, 29, proved himself a worthy contender when he knocked down Martinez in the 7th round. The scrappy Irish Middleweight seemed to throw the 37-year-old Martinez off his game until the 10th round, when Martinez took over the fight with several right hands, dropping Macklin a few times before his corner threw in the towel before the start of the 12th.

Macklin may have been winning on the judges' scorecards, but the crafty Argentine ended the bout with his quick hand speed and incredible endurance, showing again why he is considered one of the top pound-for-pound fighters in the world.

Martinez is now 49-2-2 with 28 knockouts for his career, while Macklin's record now stands at 28-4 with 19 knockouts.