Video by Ryan Burton

MANNY Pacquiao scored an emphatic victory over American Tim Bradley in Las Vegas, sealing his 21-year professional career with a polished performance in what he insists was his farewell to boxing.

Pacquiao, fighting for the first time since his defeat to Floyd Mayweather last year in the “Fight of the Century”, knocked down Bradley twice on his way to a comfortable unanimous decision.

The judges’ scorecards at the MGM Grand Garden Arena told the story of Pacquiao’s dominance, with the 37-year-old eight-division world champion winning by identical margins of 116-110 on all three cards.

Pacquiao insists Saturday’s bout -- the 66th of his career -- will be his final fight before he concentrates on his political career in the Philippines, where he is seeking election to the Senate next month.

Pacquiao had promised an explosive performance and was as good as his word for long periods, uncorking some trademark combinations to overwhelm Bradley.

A cagey opening round had the feel of a tactical battle, with Bradley carefully keeping his distance as he circled the marginally more aggressive Pacquiao, who threw 33 punches to Bradley’s 19.

The next three rounds followed a similar pattern, with Pacquiao looking the more menacing fighter, relentlessly stalking Bradley around the canvas, cutting off angles, and connecting with more meaningful blows.

Bradley landed occasionally but it was Pacquiao who did the most damage, landing a straight left that caught his American rival flush on the chin in the second round.

Bradley started confidently in the fifth round but again his good work was undone by Pacquiao in the final minute when the Filipino uncorked a series of combinations to score heavily.