David Diaz has one advantage over Manny Pacquiao despite claims that the Filipino puncher will walk through him on June 28.

“I am naturally bigger and heavier than him (as I am used to fighting in this weight class),” Diaz told the Bulletin yesterday by phone from his Chicago home.

Pacquiao, who will make his debut at 135 lbs when he goes after Diaz’s World Boxing Council (WBC) lightweight crown, enters unfamiliar territory as Pacquiao has never fought beyond the 130-lb ranks that he rules with an iron fist.

While Pacquiao has succeeded in getting the likes of Erik Morales, Marco Antonio Barrera and Juan Manuel Marquez off their feet, it is unsure if he can inflict the same kind of damage against somebody who is accustomed to the pounding at lightweight, super-lightweight (140 lbs) and even at welterweight (147 lbs).

While his last few fights have been at 135 and 140 lbs, Diaz had more than a dozen bouts weighing 140 lbs or more and in some occasions weighed as much as 147 lbs.

Diaz, who kicked off training last April 19, said the guy who “comes to the fight in the best of shape will win it” as the 31-year-old slugger guarantees that he is doing everything possible to achieve the greatest conditioning ever to get ready for “the biggest fight of my life.”

“Conditioning is going to be the key,” said Diaz, who begins sparring either late this week or next week. “My manager, Jim Strickland, knows my sparring partners and they would all be coming from all around here.”

While Pacquiao normally logs 100 to 130 rounds of sparring per training, Diaz, who has a record of 34-1-0 with 17 knockouts, is “not heavy on that” but occasionally bangs bodies three times a week.

“I don’t normally keep track on the number of sparring rounds,” said Diaz, who almost had 200 amateur fights.

In a separate interview with ace fight scribe Ron Borges last week, Diaz said “Pacquiao is a top fighter in his prime but when I look at him, I see a guy I can hit real easy. I see a guy I can beat. I honestly feel that.”

Told about talks that the 29-year-old Pacquiao will be too much for him, Diaz just shrugs it off.

“It’s the way it’s been for a long time. By now you’d think some people would give me a little bit of a chance but that’s all right. The only thing that really matters is when your hand is raised. I am pretty good at blocking out that sort of negative stuff and I stick to that. I will do everything possible to be ready. After I beat him maybe we can put a stop to that kind of thinking but I don’t get insulted by it. I really don’t.”

Diaz doesn’t make any fuss about the billing and the sharing of the purse that he knows Pacquiao, and not him, is the top draw.

“He gets the filet mignon and I get the New York cut but that’s better than nothing. The important thing is winning the fight. When I beat him I’ll be the guy they’re talking about. Until then, if you take that kind of thing personally, you corrupt your heart.”

But Diaz drools over the prospects of locking horns with the fighter many regard as the finest in the world today regardless of weight.

“What Pacquiao does is make you fight his type of fight (and) in my case that’s fine because his type of fight is my type of fight. Pressure, that’s my best offense and my best defense.”

Meanwhile, Pacquiao is beginning to taper off in his wild and wooly itinerary and plans to leave for the US on May 10 in time for a press conference on May 13 after a light workout in his hometown of General Santos City.