Pacquiao, who retained his WBC International championship title with the win, was ahead 118-109 on two judges' scorecards, and 115-112 ahead on the other.

It was Pacquiao's second victory over Barrera after an 11th round TKO in November 2003.

"It was a good fight," said Pacquiao.

"It was different from our first fight. He is a good, smart boxer. I knew he'd have to box me, and that's what he did."

Although the bout was widely expected to be explosive, it was frequently tactical, with Barrera working behind a steady jab and circling to his left to stay away from Pacquiao's powerful southpaw left hand.

However, after a relatively cautious opening four rounds, the fight came to life in the fifth.

Barrera landed an uppercut, Pacquiao responded with a left hand and the two exchanged furious combinations against the ropes.

The sixth round saw more toe-to-toe action but in the following rounds Pacquiao increasingly asserted control, moving to his right to cut Barrera off and unloading flurries of punches before the Mexican could counter.

In the 11th, a solid left hand from Pacquiao drove Barrera to the ropes but he fought back with a flurry before being hurt again with another right-left combination.

As referee Tony Weeks moved in to separate them from a clinch, Barrera threw a punch on the break, causing Weeks to halt the action and deduct a point.

"He has such a strong defense, it was difficult to break through," Barrera admitted after the fight.

"I'm sad because I lost the fight, and he didn't land many punches. He didn't hurt me. I thought I controlled the fight with my left hand."

The former three-times world champion confirmed his intention to retire from boxing.

"Honestly, this was my last fight," he said.