Tough way to grow up, everything happening so fast, so furious, all in one night. You suddenly age 10 years in about the time it takes to watch a Gilligan’s Island rerun.

That’s what happened to Julio “The Kidd” Diaz. He went from a boy to a young man in one ugly night and 10 brutal rounds. It was a hardnosed lesson, but nothing comes easy in his line of work.

But Diaz tells it better. He’s the one who got cut over both eyes, who couldn’t see, who didn’t quit, who went down twice in the tenth.

“I think mentally, I came out (of the fight) a lot better,” Diaz says of that hard night back in March 2005 when he was stopped by Jose Luis Castillo in the tenth round. “I fought as a baby with Castillo. That is the reason I took that fight. I wanted to get spanked and learn my lesson. I kind of had that mentality and everything went good. I was never knocked out. I was never on the ropes in trouble.”

Yeah, but he couldn’t see.

He says it was his battered eyes that frustrated him the most that night. He was cut over the left eye early by a headbutt, and was cut over the right eye in the middle rounds.

Then everything started to swell, blocking his view. You can’t hit what you can’t see. But worse, you can’t duck what you can’t see.

“I could not see because of the cuts,” says Diaz (33-3, 24 KOs), who learned a lot about himself that night. “I am not used to getting beat up like that. So it was more out of frustration. But I was never hurt. I came back and got another knockout after that and I have been on a streak since and got even better. I have matured and I have been a destroyer ever since. I am more excited now.

Diaz, who lives in Indio, Calif., tells us this on a conference call promoting his IBF title fight Saturday night (SHOWTIME) against Jesus “El Matador” Chavez (42-3, 29 KOs) at the Silver Spurs Arena in Kissimmee, Fla.

It’s a big fight for Diaz, but right now, he’s still remembering that night almost two years ago when he was taught a few lessons, Castillo doing most of the teaching.

“So, in other words,” somebody asks him on the call, “the kid became a man after that fight?”

“Right,” Diaz says. “Because I needed it. If I had to do that fight again, honestly, believe it or not, I would prefer it go just the way it went. I do not have any regrets.”

That’s why Diaz is feeling good about his chances against Chavez. He says Chavez is a great junior-lightweight, but Diaz himself is a great lightweight. At 5-foot-9, he’s about four inches taller than Chavez, and he says he’s faster.

And while Diaz has had three fights and three wins since his loss to Castillo, Chavez, who fights out of Austin, Texas, hasn’t fought in 16 months.

Part of the reason for the long layoff were injuries to Chavez. Part of the reason might be the tragic death of Leavander Johnson, who died of head injuries following his fight with Chavez in September 2005.

But Diaz, brother of top contender Antonio Diaz, isn’t counting on Chavez to maybe hold back if he gets Diaz in trouble. He doesn’t think memories of Johnson will be haunting Chavez in the ring.

Diaz is expecting just the opposite, saying Chavez is probably more motivated because of the long layoff.

“I think I‘m going to see the same person,” Diaz said, referring to the old Chavez, the one who beat Carlos Hernandez in May 2005. “I’m pretty sure he’ll be fine once the lights are on him and he is on stage.”

Sounds like Diaz has outgrown his nickname.