When the consensus #1 and #2 athlete in their sport/weightclass go at it , it’s truly something special. Just this year we had one of the most thrilling men’s tennis finals in Grand Slam history with Roger Federer and Rafael Nadal’s match at Wimbledon. Past showdowns, whether it’s Tiger Woods vs. Phil Mickelson, Fedor Emelianenko vs. Antonio Rodrigo Nogueira, Muhammad Ali vs. Joe Frazier, or Bjorn Borg vs. John Mcenroe provide the thrill and excitement of seeing the very best the sport has to offer do battle.

Tonight, fans will get the pleasure of seeing the two best welterweights in the world fight, but while the UFC has solidified their position as the number one MMA company on the planet over the past few years, they haven’t been able to put together as many consensus #1 vs. #2 fights as you might think.

Lets take a look at what they have to show for in each weight class over the last five years.

Heavyweight

You need to have the consensus #1 fighter in the world on your roster for the these match-ups to take place. Fedor Emelianenko is the best heavyweight MMA fighter bar none, and he ain’t in the UFC. In Pride, Emelianenko fought current UFC champ Nogueira on New Year’s Eve 2004 when they were ranked by pretty much everyone as number one and two respectively. Also in the Summer of 2005, Fedor fought Mirko Cro Cop who was widely ranked at #2 or #3 behind Nogueira at the time as well.

It doesn’t look like one of these heavyweight superfights will be taking place in the UFC anytime soon, although the winner of October’s bout between Andrei Arlovski and Josh Barnett will have a strong argument as one of the three best heavyweights in the world, and will likely face Emelianenko in 2009.

Light Heavyweight

This division has a much different landscape than heavyweight, with several elite fighters in the top ten that have been considered the best in the world at different points in their career. Just under five years ago Randy Couture fought Tito Ortiz to unify the UFC light heavyweight title, and one could argue that those two men were the best in the world at the time. Would I agree? Probably not, largely due to the fact that Pride’s 2003 MWGP was taking place at the same time featuring Wanderlei Silva and Quinton Jackson. This is an issue that faces Couture-Liddell II and Ortiz-Lidell II as well. There was no way of knowing who was better at the time between Pride and the UFC, because so many of the top fighters hadn’t fought each other.

Middleweight

Anderson Silva is without question the best middleweight fighter in the world, and has been steamrolling through excellent competition for a few years now. The second Franklin fight as well as the showdown with Dan Henderson were definite #1 vs. #2 candidates, but there are still many top middleweights outside the UFC. The winner of the DREAM GP(I’m thinking Jacare or Mousasi) will likely be knocking on the door of the top ten(if not top five). Bitter rivals Yoshihiro Akiyama and Kazuo Misaki are top fighters, as well as Affliction’s Matt Lindland and EXC’s Robbie Lawler.

Welterweight

For the last five years, the UFC’s welterweight division has been its most talent-rich as far as top twenty-five fighters go. For a large chunk of this time, Matt Hughes was considered by most as the best welterweight on the planet, and he fought and bested many of the top fighters around. It’s safe to say that Hughes’ second fight with GSP was between #1 and #2, and you could argue that a few other Hughes defenses from the last five years fit that criteria as well

Even without having Jake Shields under contract, there is a wealth of great fighters at 170, so whoever the titleholder is, he will likely be facing only top-five competition for the foreseeable future.

Lightweight

In the last five years 155 has been the most fractured weight class as far as talent dispersal is concerned, and because of this, you could argue that no promotion has had the undisputed two best lightweights in the world fight each other. B.J. Penn’s fights versus Takanori Gomi in Hawaii and Sean Sherk in the UFC are close, although Gomi was coming off a loss, and despite wins over Florian and Franca, hadn’t proved himself enough at lightweight to deserve the title of second best. Don’t expect to see the air cleared in this division anytime soon with the UFC, WEC, DREAM and Sengoku all having competitive lightweight classes.

Is Fitch #2?

There is no question in my mind that Jon Fitch is the second best welterweight on the planet, and will give Georges St. Pierre his toughest test to date. I tend to agree with Jonathan Snowden’s take, and disagree with my other Total-MMA colleagues who wrote off Fitch’s chances in this weeks podcast.

Fitch’s rise to the shot has been very impressive. He destroyed Josh Burkman and Thiago Alves, battled through adversity to choke out Roan Carneiro, and is the only man to actually “fight” Diego Sanchez and win. Tonight’s bout should be close, go long, and be fitting of the moniker “#1 vs. #2″.