It will be the fourth time the two boxers will square up in the ring, Pacquiao having narrowly6 retained his WBO welterweight title with a controversial majority decision when they last met in November 2011.
On that occasion, the Filipino southpaw earned two of the verdicts from the three judges, though it was a surprisingly unimpressive display and boos from disgruntled Marquez fans echoed around the arena after the shock decision was announced.
"Right now my mind is focused on being more aggressive for this fight," Pacquiao told reporters while preparing for the Dec. 8 bout at the MGM Grand Garden Arena in Las Vegas.
"If there is a chance in the ring during the fight, why not make the fight easy (by knocking Marquez out) if I have the opportunity?
"I will try not to fight as slow at the end of this fight as I did in the last three fights. That is my focus right now. I want to finish stronger in this fight."
Mexican Marquez is a three-division world champion and, according to Pacquiao's shrewd trainer Freddie Roach, he has been the Filipino's most difficult opponent over the years.
"A 100 percent yes," the bespectacled Roach told Reuters. "Manny loves it when guys come to him and they're aggressive.
"Marquez is a counter-puncher and we're probably going to have to go to him to make the fight happen. It's a little harder for Manny to do that, so it's the most difficult style for us, yes."
Marquez and Pacquiao are both renowned for their bold, all-action approach in the ring and they fought to a draw when they first met in May 2004.
The Mexican then lost his WBC super-featherweight title to the Filipino in a controversial one-point split decision in March 2008.
In 2011, Pacquiao was tested to the full in their third encounter before he stunningly beat a visibly angry Marquez after the Filipino's preparations had been hampered by various distractions, including marital difficulties.
Since then, however, he has patched up his relationship with his wife Jinkee and become a much more disciplined boxer after replacing his former pastimes of cockfighting, gambling and nightclubbing with increased bible study and family time.
"I always train hard, but this time is a little harder with more punches," Pacquiao said of his strenuous preparations with Roach at the fabled Wild Card Boxing Club in Hollywood, California.
"We have been throwing more combinations, and changing our strategy - in movement. So it will be a little different than the last one.
"I am giving him a chance to prove he can win the fight because he thought he has won all three and he keeps talking about it. So it is very important to me, to win this fight."
Pacquiao has won world titles in an unprecedented eight weight divisions and Roach has been delighted by his fighter's unwavering and steely focus in training.
"I like what I see," Roach said. "He is where I want him to be right now. His focus is where it has not been for some time. I think it's going to be the best fight yet."
Pacquiao lost his most recent fight on a hotly disputed split decision to American Timothy Bradley in Las Vegas in June, but Roach feels no added pressure for the Filipino to prove himself against Marquez.
"No, I just do the job the best I can to get Manny ready for this fight," Roach said. "I thought Manny won that last fight 11 rounds to 1 so I don't really consider that a loss. It's just business as usual."
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