Mayweather, unbeaten in 48 professional fights stretching back to
1996, retains his WBC and WBA welterweight titles and takes the WBO
belt from Pacquiao.
The American was caught with the odd good shot, but was quicker
throughout and always looked in control.
The judges scored the fight 118-110, 116-112, 116-112.
At a 16,000 sell-out MGM Grand Garden Arena in Las Vegas – where some
spectators had paid as much as $350,000 for tickets on the resale
market – Mayweather, 38, started much the better of the two fighters.
Mayweather bossed the early rounds before Filipino Pacquiao had
success in the fourth with a couple of strong left hooks to the head.
But the American always dominated and largely stayed out of trouble,
keeping Pacquiao at arms length with his superior footwork.
Noisily backed by the 16,000-strong crowd, Pacquiao, 36, continued to
have the odd success – landing a strong left in the eighth – but
Mayweather's speed and movement proved key, and as the fight wore on
he began to have more success.
The 11th was the most one-sided of the contest as Mayweather, looking
as fresh as he had in the opening round, picked off a tired-looking
Pacquiao almost at will.
Mayweather avoided Pacquiao's increasingly ragged attempts to land in
the final round and comfortably won on all the judges' scorecards.
The fight, watched by celebrities and sporting stars, is expected to
generate an estimated $400m (£265m).