In 2007, as PRIDE FC was nearing its end, Mauricio "Shogun" Rua was considered (arguably) the top 205-pound fighter in the world.

At 25, he was already one of the promotion's crown jewels with the 2005 Grand Prix title. He was the best light heavyweight in the world according to many publications, even during the time Chuck Liddell was executing his reign of terror on the UFC light heavyweight division to the tune of four title defenses, while simultaneously piggybacking the sport of mixed martial arts and dragging it closer to the mainstream.

His resume reads like a "who's who" list of MMA fighters, with victories over former UFC light heavyweight champion Quinton "Rampage" Jackson, Antonio Rogerio Nogueira, current Strikeforce heavyweight champion Alistair Overeem (twice) and former UFC heavyweight champion Kevin Randleman.

Once the UFC officially bought out and acquired PRIDE FC, Rua was immediately thrown to the wolves stateside.

Rua's career had been mostly filled with highs up to this point in time, but he would soon be rudely welcomed by numerous challenges that would test his will, not only as fighter, but as a man.

In September 2007, in his UFC debut, he was paired up against The Ultimate Fighter Season 1 winner Forrest Griffin. Rua entered the bout as a heavy favorite but lost via rear naked choke late in the third round. It was a major disappointment for the much-heralded Brazilian.

Rua was noticeably gassed throughout the fight due to poor cardio, most likely due to the fact that he had suffered a knee injury during his training for the fight. Shortly thereafter he had surgery to repair the knee, but his bad luck did not end.

After completing many months of rehabilitation, he once again blew out his knee in training, which forced him to be pulled from a UFC 85 matchup with Liddell. The recovery and rehab once again would wear on him mentally and physically for many months.

Finally healthy, and 16 months without a fight, he took fought at UFC 93 in January of this year. The out-of-shape Rua was able to defeat Mark Coleman by TKO late in the third round, but to most fans and media, Shogun's performance was lackluster at best. Many wondered if Rua would ever be even a shadow of his former self.

To be fair, however, any MMA fighter who is removed from training and competition for that span of time would struggle in his return.

After all, being in good physical shape and being in fighting shape are two very different things.

His luck would finally swing in his favor in April 2009 in his next fight at UFC 97, where his performance would be the antithesis of his previous bout. A vicious left hook by Rua sent Liddell to the canvas in the first round, where he promptly pounded him with hammer fists until the referee stopped the fight. A healthier, fresher, and better conditioned Rua had now shown glimpses of the kind of fighter he could still be, the kind of fighter he once was.

Subsequently, the UFC granted him a title match against current UFC light heavyweight champion Lyoto Machida, which be Rua's toughest test of his still relatively young career.

"The Dragon" has become one of the most feared MMA fighters in the world in a short time span. He has an unorthodox, unique style that has created a matchup problem no man has been able to counteract up to this point. Currently he is 15--0 in his professional MMA career and 7-0 in the UFC.

According to Rua, "I think what makes him so unique is his background, karate, and how he adapted it to his own MMA fighting style."

He continued discussing his impending challenge stating, "When you fight other fighters, they usually have a background of boxing or kickboxing, striking-wise, so it's something you are used to deal with, as you have been training with those kind of fighters through your whole life so you know their distance, timing, etc..."

Not the case with Machida.

"Lyoto is usually something you never dealt with, or at least not so often, and until you figure his style out, sometimes it's too late. My team and I watched a lot of tapes and did our homework," said Rua.

It's true. Machida barely ever gets touched inside the cage, much less defeated. In other words, Rua is coming into the fight as a heavy underdog.

"During most of my career I was always used to be the underdog. I was the underdog for my last fight with Chuck Liddell. I was the underdog in PRIDE when I fought Quinton "Rampage" Jackson, and I was the underdog on the whole PRIDE GP in 2005 so it's nothing new," said Rua.

It's familiar ground for Rua, and instead of rejecting the notion, he's chosen to not only accept, but to relish the position.

"I even like being the underdog. This way I feel I have much less pressure and it's the other guy's obligation to beat me. I feel like I have only the obligation to do my best and I have much more to gain than I have to lose," said Rua.

Rua-Machida will also mark another milestone for the UFC's light heavyweight division. It's a battle between a former world No. 1 trying to work his way back to top of the mountain and the current world No. 1, who is trying to fend off all combatants who have championship aspirations.

"It (championship belt) would mean a lot. It's what we work for, what we train for, and the ultimate goal any fighter can have right now.

"The UFC is the biggest fighting promotion in the world, has the best fighters and I think the 205-pound weight class is likely the toughest class in the game, so to become the champion in the biggest show and on the toughest weight class means the world, " said Rua.

Will Rua be able to shock the world and become the first man to ever beat Machida?

"I only want to go in there and do my best. I feel always obligated to put my best effort to give the fans what they want to see, an exciting fight. I want to win and I fight to win."

SI Apps
We've Got Apps Too
Get expert analysis, unrivaled access, and the award-winning storytelling only SI can provide - from Peter King, Tom Verducci, Lee Jenkins, Seth Davis, and more - delivered straight to you, along with up-to-the-minute news and live scores.