Manny Pacquaio believes his greater speed will be crucial to his chances of ending the undefeated streak of Floyd Mayweather Jr.
The pair are entering their final preparations for Saturday's Las Vegas superfight, hotly anticipated the world over.
Both fighters arrived on the strip on Tuesday, and Pacquaio was quick to deliver a warning shot to Mayweather, who heads into the fight protecting his precious 47-0 record.
"I'm different to the 47 opponents he has fought before. I'm faster than them and I'm content for the fight. I believe this is the moment he will experience his first loss," Pacquiao said.
"I can't say Mayweather is the most dangerous opponent of my career because I've fought guys like Oscar De La Hoya, Miguel Cotto, Juan Manuel and Marquez and other boxers.
"He's a difficult opponent but my confidence is different for this fight. This is one of the most important fights for my boxing legacy.
"I have to prove something. Every time I'm the underdog, I like that because my killer instinct, my focus is there. This is what I want.
"We're not working one strategy, but we have two or three. If he wants to fight me, that's good for me.
"But if he's running and running and moving around the ring, we've prepared for that."