Porter, a former IBF welterweight champion, dominated the fight until the 11th round, scoring by a wide margin in the weekend non-title fight.
In the last round, Broner surprised Porter with a power left hook that sent Porter down, but managed to beat the count and resumed fighting until the end of the round.
Except for the last round, the fight was lopsided in favor of Porter, who was clearly ahead on points until the 11th round as Broner remained tentative on his assault and stayed away from Porter in most of the rounds.
Veteran referee Tony Weeks was widely criticized for allowing Broner to hold and for making foul shots but he eventually deducted a point from Broner in the later round for excessive holding.
Judges scorecards: 118-108, 115-111 and 114-112, all in favor of Porter for a unanimous decision win.
“That’s how you beat a great fighter,” Porter said after the fight. “We wanted to established dominance.” he added.
For his part, Broner said: “At the end of the day, great champions can take a loss like they take a win.”
Both fighters are aiming for a lucrative fight against Mayweather, who is returning to the ring on Sept.12 following his unanimous decision win against Filipino boxing star Manny Pacquiao last May 2 at the MGM Grand in Las Vegas, Nevada.
With the win, Porter improved his career record to 24-1-1 while Broner dropped to 31-2-0.
