MIAMI - Little did Manny Pacquiao envision when he walked into the ring for his first professional match 13 years ago that he would one day perform in one of boxing's most anticipated fights - and at a prohibitive heavier weight.

When Pacquiao made his debut in his native Philippines, he fought in the 106-pound, junior-flyweight class. Pacquiao eventually ascended through weight divisions and in stature.

On Saturday night, Pacquiao will do what at one time was considered unimaginable. Now recognized by many experts and fans as boxing's best pound-for-pound fighter, Pacquiao will face Oscar De La Hoya in Las Vegas - as a welterweight, which is 140 to 147 pounds.

"Inside the ring, I'm doing my job," Pacquiao, 29, said in a conference call last week. "This is the fight of my life, so I have to do everything during the fight and to make the people happy."

So far, Pacquiao has pleased millions of boxing fans through his entertaining performances and victories over notable world champions. Pacquiao (47-3-2, 35 knockouts) has won world titles in the flyweight, junior-bantamweight, super-featherweight and lightweight divisions - a noteworthy feat considering the 23-pound span of weight classes.

In the Philippines, Pacquiao has become a cultlike symbol. The country virtually shuts down when Pacquiao fights and similar attention is expected for Saturday's bout against De La Hoya.

De La Hoya, 35, knows the glare of the spotlight. Winner of world titles in six separate weight divisions, De La Hoya (39-5, 30 KOs) is the sport's most popular fighter. His bouts, including Saturday night's, usually come with pay-per-view designations.

Actually, De La Hoya even makes money for his opponents. Floyd Mayweather Jr., Felix Trinidad and Shane Mosley solidified their pay-per-view profiles after their bouts against De La Hoya.

"I am fortunate to have a worldwide stage that has paid attention to my career, and Manny Pacquiao has a huge following, too," De La Hoya said after a recent workout. "Now we are all over the place, and the whole world is paying attention to this fight and wondering what the outcome is going to be.

"That in and of itself is a thrill, for me to be a part of another great event."

The story line for Saturday's fight is the 5-foot-6 Pacquiao facing the 5-10 De La Hoya and moving up to the 147-pound welterweight limit. De La Hoya has spent most of the last 10 years fighting in welterweight and junior-middleweight bouts.

Will Pacquiao's speed and power still carry significant clout against a taller and bigger foe?

"You can see in my last few fights that my style is always changing," Pacquiao said. "So I think for this fight, we have a couple of techniques that I can't talk about it right now but you will see in the fight. And maybe people will be surprised there.

"You know, it's going to be boxing history."