Manny Pacquiao is out to prove that his best days are still ahead of him when he takes on Timothy Bradley in their rematch on April 12 at the MGM Grand in Las Vegas.

While Pacquiao has been content winning by decision in his last several fights, he's made it clear that he will go for the kill against Bradley, who scored a controversial split-decision win during their first showdown.

In an interview with Yahoo Sports, Pacquiao, who is coming off a one-sided decision win over Brandon Rios in November, said that he will be very aggressive in his rematch with his former tormentor.

Pacquiao said that he is unsure whether or not Bradley will continuously run away from him like in their first fight, but the former pound-for-pound king vowed that he will constantly pressure the reigning WBO welterweight champion in their second fight.

"The focus this time is on aggressiveness," Pacquiao said. "I don't think he's going to try to go toe-to-toe with me, but I have to be more aggressive than I had been. I have been working on being aggressive."

Trainer Freddie Roach, who recently said that he is expecting a tough fight against the 30-year-old champion, also revealed that Pacquiao is determined to score a knockout this time.

Roach said that Pacquiao has been playing it safe over his last few fights, including against Rios, who Pacquiao looked capable of knocking out.

But against Bradley, Roach said that Pacquiao is itching to score a knockout victory after Bradley said that the former eight-division champion has already lost the killer instinct that once made him one of the most feared fighters in the world.

"The difference this time is that Bradley said it to him. Bradley said at that first press conference that Manny lost his killer instinct," Roach said. "That must have bothered him, because more than once, Manny has said to me, 'Can you believe he said that to me?' And you can see by the way he's working, he wants to give people what they want, which is a knockout."

Pacquiao, who has started training at the Wild Card Gym in Los Angeles, has not scored a knockout victory since his 12th-round stoppage win over Miguel Cotto in November 2009.