Manny Pacquiao made a successful return to the boxing ring, pounding Jessie Vargas to win the WBO welterweight title via a unanimous decision.

The Las Vegas bout went the full 12 rounds on Saturday but Pacquiao (59-6-2) was the superior fighter as the 37-year-old ended his short-lived retirement in victorious style.

Pacquiao retired following his victory over Timothy Bradley in April before he was elected to the Philippines Senate a month later, but the lure of boxing was too strong.

And Pacquiao's return to the ring attracted a keen onlooker, with rival Floyd Mayweather - who is retired - an unexpected guest ringside ahead of a potential rematch, following the pair's blockbuster showdown won by the latter in May last year.

Filipino Pacquiao hit the ground running at Thomas & Mack Center, flooring his 27-year-old opponent (27-2) in the second round with a quick left-hand counter.

Pacquiao continued to look comfortable from that point, showing signs of his trademark speed, despite a brief stint outside of the ring.

Vargas did manage to find some rhythm but Pacquiao was largely untroubled as chants of "Manny!, Manny!" echoed around the arena.