Floyd Mayweather Jr claimed victory over Manny Pacquiao on a points decision in Las Vegas this evening to remain unbeaten and move to 48-0 in his professional career.

The judges declared the 38-year-old the winner by unanimous verdict as they scored the bout 118-110, 116-112 and 116-112 to allow the American to become the unified welterweight champion by adding Pacquiao's WBO title to his own WBA and WBC belts.

The American began the fight in an aggressive fashion as he landed a couple of right hands on the chin of the 36-year-old, using his reach and tight defence to his advantage.

Pacquiao responded with a strong second round as he pushed Mayweather into the corner, but was unable to land a telling blow on the American, who then caught him with a solid right counter before the bell.

The brawlers battled out an even third round before the Filipino launched an assault on the American as he pinned him to the ropes and landed a series of body shots to make an impact in the fight.

Mayweather came out with a strong response in the fifth round as he took the initiative to land a couple of blows to the body of Pacquiao, while avoiding the counter punch from the Filipino.

However, the 36-year-old hit back at the American with a series of punches to the body as he forced him into a corner and had a solid spell of pressure before he relented to take the sixth round.

Mayweather applied pressure in the opening stages of the seventh to knock Pacquiao out of his rhythm, but the Filipino responded with a right hand, although the American did enough to see off the threat to land further blows and extend his lead in the fight.

Pacquiao came out with a powerful left hook in the eighth to surprise his opponent, who hit back with two quick blows on the counter and was solid in defence to ensure that the Filipino could not take the round cleanly.

The Filipino failed to land the meaningful blows he required in the ninth round to close the gap on the American as Mayweather displayed his quality in defence by weaving away from Pacquiao's range.

Mayweather's advantage in the bout allowed him to dictate the tempo as he managed to avoid getting into close exchanges with the Filipino and continued to use his reach to fend off his advances as time slipped away.

The American produced his strongest round in the 11th as he landed several shots on Pacquiao to take the fight away from the Filipino with a series of quickfire jabs, which the 36-year-old was unable to respond to as Mayweather put himself on the brink of victory at the bell.

The 38-year-old used his experience in the final round to avoid Pacquiao's punching power on the inside, securing a unanimous points decision at the MGM Grand Arena.