Pacquiao (59-7-2, 38 KOs), who turns 40 in December, takes his traveling road show to Kuala Lumpur, Malaysia, in a fight that should produce fireworks considering the power punching and brawling style of the 35-year-old Matthysse (39-4, 36 KOs).
Following his shock loss to Australian journeyman Jeff Horn last time out, Pacquiao chose to change his corner team, and his new line-up paid immediate dividends.
FIST PUMP. President Rodrigo Duterte and Malaysian Prime Minister Mahathir Mohamad do the Philippine leader's traditional fist pump gesture alongside boxing champ Senator Manny Pacquiao.
More clubbing blows sent Matthysse to the canvas again in the fourth round after a hook to the temple.
As referee Bayless gave Matthysse the count, the champion spat out his mouthguard prompting the stoppage.
However, Pacquiao refused to be moved after the fight when asked about a potential next opponent.
"I'm surprised I knocked him down so early - in the third, fifth and seventh". We were not pushing hard - we controlled our pace and ourselves.
Duterte, in a statement, congratulated Pacquiao for uniting and giving the Filipino people pride in the boxing arena.
"We have a good president", Pacquiao said amid "Duterte" chants from his supporters who joined him on the boxing ring, including Bureau of Corrections chief Ronald Dela Rosa.
"He (Pacquiao) has so much money already, no problem", the President quipped. "He's a great fighter".
"You have proven time and again that you are not just a public servant, but one of the greatest boxers of all time", the President said.