The 33 year-old came out wanting to trade with the younger Porter, 26, from the first bell and was quickly cut on his left cheek in the opening exchanges.
Porter connected with several huge shots as Malignaggi was caught square-on time and again until eventually the Italian-American went down in the fourth. A further barrage from Porter pinned Malignaggi up against the ropes and following several clean shots, ‘The Magic Man’ crumbled to the canvas and referee Sam Williams waved it off.
It was a huge statement from Porter, who never allowed Malignaggi to get into a rhythm with his jab as ‘Showtime’ retained the IBF welterweight belt he ripped away from Devon Alexander previously.
Earlier, WBO middleweight champion Peter Quillin retained his title with an easy victory over former light-middleweight world title holder Lukas Konecny on the scorecards.
Quillin, 30, looked a monster compared to the slighter Czech fighter after blowing up to 179lbs since Friday’s weigh-in, and was never troubled for the duration of the fight as the American won every round.
Konecny attempted to get inside and rough up Quillin, although the superior reach of ‘Kid Chocolate’ kept the 35 year-old at bay, with the judges seeing it 120-108 and 119-109 twice for a straightforward victory.
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