Lucas Matthysse will have "no respect" as he seeks to knock out Manny Pacquiao and defend his World Boxing Association welterweight title in Sunday's showdown that could cap an illustrious career for the Filipino sports icon.

Both fighters were comfortably below the 147-pound limit when they stepped on a scale Saturday ahead of their match, dubbed the "Fight of Champions."

An 11-time champion across eight divisions, Pacquiao weighed in at a trim 146 pounds while Matthysse tipped the scales at 146.7 pounds.

"I know Manny Pacquiao brings an intense energy in a fight, so we are ready for that. All we need to do is just to keep composed, make sure that he is ready to catch Manny at the right time and have no respect for Manny," Matthysse's trainer, Joel Diaz, told The Associated Press after the weigh-in.

The main advantage for Matthysse, known by his nickname "The Machine" for winning 36 out of his 39 matches by knockout, is his strength and ability to deliver power punches from both hands, Diaz said.

"All I can say is this...it's not going to be an easy fight for Manny Pacquiao. If Lucas lands any punches on Pacquiao, he will hurt him because he hits real hard," Diaz added.

"Lucas Matthysse is stepping up to the level of opposition. He's fighting against a legend and he's in the best shape of his life. Everything is at stake for him. He is defending his title and secondly, he knows by beating Manny Pacquiao, it will be in the history books."

"Pacman" Pacquiao, who turns 40 in December, returns to the ring a year after his shock decision loss to Australia's Jeff Horn in Brisbane.

Pacquiao, 39, has won 59 times, including 38 by knockout, and lost seven times (three by knockout) along with two draws.

It will be the first time since 2001 that Pacquiao is fighting without longtime trainer Freddie Roach, who was dropped in the run-up to the Malaysian fight and replaced with former assistant coach and friend Buboy Fernandez.