Pacquiao, as expected, threw more punches than his opponent, in the 12 rounds, often taking the fight to his opponent. But #Mayweather was able to dance his way out of trouble while doing enough damage with his straight punches to convince the judges.
The American took the most lucrative contest in boxing history 118-110, 116-112, 116-112. But the crowd at the MGM Arena booed the decision.
The BBC reports that Mayweather, 38, delivered a defensive masterclass against his Philippine rival, making the necessary adjustments after only a few rounds before disappearing out of sight.
Mayweather, who added the WBO welterweight title to the WBC and WBA titles he already owned, was awarded the fight 118-110, 116-112 and 116-112 by the three judges.
With his victory, Mayweather also cemented his status as the greatest pound-for-pound boxer of his generation.
The five-weight world champion is now undefeated in 48 professional fights, stretching back 19 years.
Six-weight world champion Pacquiao, 36, falls to 57 wins, six losses and two draws.
Tickets for the bout – billed as ‘The Fight of the Century’ – changed hands for as much as $350,000 (£232,000) and American fans were charged almost $100 (£66) to watch on television.
Rival broadcasters Showtime and HBO joined forces for the first time since Lennox Lewis fought Mike Tyson in 2002 to show the fight, with Jimmy Lennon Jr and Michael Buffer sharing ring announcer duties.
A-listers in attendance included Clint Eastwood, Robert De Niro, Sting, Prince and Donald Trump, Justin Bieber, Jay-Z and Beyonce, Jesse Jackson, while multi Grammy Award winner Jamie Foxx sang the American national anthem prior to the fighters entering the ring.
So prized was a seat that many celebrities were even sat behind the press row.
*with reports by BBC