For any boxer, landing a fight with pound-for-pound and pay-per-view king Floyd Mayweather Jr. is like hitting the lottery. It means a life-changing pay day in the millions and a huge spotlight.

Robert Guerrero, one of the stars of boxing -- but not well known to the mainstream -- got the winning lottery ticket on Tuesday when he officially landed a long-rumored fight with Mayweather, whom he will challenge for a welterweight world title on May 4 (Showtime PPV) at the MGM Grand in Las Vegas. The fight is Mayweather's first since bolting from career-long television home HBO to sign a boxing industry-shaking six-fight, 30-month deal with Showtime/CBS, which was announced in conjunction with Guerrero as his opponent earlier this week.

Robert Guerrero, pictured here in a 2011 fight with Michael Katsidis of Australia, will take a 31-1-1 record into his fight with Floyd Mayweather Jr. AP Photo/Isaac Brekken

Guerrero has campaigned for the fight for more than a year and was thrilled to get word that he had it.

"Just excited, the family's excited," Guerrero said Thursday on a conference call with a handful of reporters, his first public remarks since getting the fight. "Couldn't be happier. This is the fight we've been looking for and training for. I'll be 100 percent prepared. I'm ready for the fight. We're getting that game plan together, me and my father (Ruben Guerrero, also his trainer), and not letting anything distract me. I can change gears and adapt. I'm pumped.

"I can't wait to show the world why I am the best fighter in the world."

Two weeks ago, Mayweather tweeted that injured welterweight titlist Devon Alexander, who already was under contract for another fight that was postponed, was the leading candidate to get the May 4 fight. No serious negotiations ever took place, according to Alexander promoter Richard Schaefer of Golden Boy, which has promoted Mayweather (43-0, 26 KOs) on a fight-by-fight basis since 2007.

Still, Guerrero saw the tweet and heard the speculation. He was concerned he might not get the fight. How does he feel now?

"Just relieved. A lot of relief," Guerrero said. "Throughout my career, I jumped through the weight classes because guys were ducking me, being right there and not being able to get the big fight because I was being avoided. So when you hear all the names coming up, Alexander, (Timothy) Bradley, you think, 'Is this guy (Mayweather) going to duck me or what?' So I was just relieved everything got signed and done and I can't wait for the fight.

"Definitely, I'm ready for (the spotlight). What God has put me through to be prepared for this, not just physically but mentally, all the stuff inside the ring and outside the ring, prepared me for this. It's time."

Guerrero said he plans to end Mayweather's undefeated run. He sees Mayweather as a fighter in decline.