Silva vs. Sonnen: Each Fighter's Defining MMA Moment

Chael Sonnen and Anderson Silva are the two best middleweights in the world. Both men have pushed their way through the ranks over the years, spanning through various promotions.

The rematch of UFC 117 goes down tonight, with the winner undoubtedly becoming the No. 1 middleweight in the world. Here is each fighter's defining moment leading up to the fight.

Silva Faces Adversity, Submits Biggest Challenge to Date

Facing a brash American in Chael Sonnen, Anderson Silva was expected to walk through his fight at UFC 117, as not many people expected Sonnen to provide much of a challenge.

There was a lot of trash talk from Sonnen leading up to the fight, which definitely hyped the event up. 

The fight came and it saw Sonnen absolutely dominating at the outset. Using his wrestling and ground striking, Sonnen looked as if he would knock off the No. 1 pound-for-pound fighter in the world.

Even more surprising, Sonnen dropped Silva on his feet twice. A pure wrestler hurting the best striker in the world with a punch may have shocked the audience more than anything else.

Losing the first four rounds, two of which were 10-8 rounds, Silva had to finish the fight in the fifth round. With under two minutes left, he threw a Hail Mary, which was caught for a touchdown.

Silva got a hold of Sonnen from the bottom, grabbed an arm and locked it in a picture-perfect triangle armbar. Stuck in the hold with too much time remaining, Sonnen was forced to tap in the biggest shocker of the fight.

Silva retained his title under great duress, showing the heart of a champion. This fight set up the rematch tonight, as Sonnen is the first person to ever get that close to beating Silva.

Either way, it was "the Spider's" defining moment.

Sonnen Returns from Suspension, Submits American Hero and Calls Out Nemesis

One could argue that UFC 117 was Chael Sonnen's defining moment, as it put him on the map. But I will have to go with UFC 136's win over Brian Stann.

Coming off a long suspension from his elevated testosterone fiasco following UFC 117, many speculated that Sonnen would be rusty. Sonnen would prove he was no such thing, as he walked through the fan favorite, Stann.

Even better, Sonnen was able to defeat Stann via submission by arm triangle choke. This is significant because it showed Sonnen had improved his submission game since his devastating defeat at the hands of Anderson Silva.

Following the fight, Sonnen made an epic callout on his rival Anderson Silva. After telling Silva that he sucked, he made the biggest proposal of all time.

He stated that if he won, Silva would need to leave the division. If Silva won, Sonnen would cease fighting. It was the most epic post-fight interview of all time and cemented the necessity to have a rematch between two of the biggest rivals in the sport's history.