When George Sotiropoulos defeated Joe Stevenson at UFC 110 to begin his UFC career a perfect 5-0 in the Octagon, he joined a very select group of fighters.

Only 12 active fighters on the UFC's current roster have begun their UFC careers with five straight wins, and the names on that list might surprise you. 

Georges St. Pierre, BJ Penn, Matt Hughes, Chuck Liddell, and Tito Ortiz are not on the list. Nate Marquardt, Gabriel Gonzaga, and Dan Hardy all got their title shots after starting 4-0, and Marquardt and Gonzaga all saw their records fall to 4-1 afterward, with Hardy facing stark odds at UFC 111 against current welterweight juggernaut, Georges St. Pierre.

Among UFC lightweights, top contenders Frankie Edgar, Gray Maynard, Tyson Griffin, Sean Sherk, and Kenny Florian weren't able to achieve 5-0 starts. In fact, Sotiropoulos is the only active lightweight who has.

So, who are the dozen fighters in the "5-0 Club"? I'll count down the list from the top.

Anderson Silva, 10-0. Silva started his UFC career by breaking the unbeaten streaks of two other men, and seized the middleweight belt in just his second match, with a knockout of Rich Franklin at UFC 64: Unstoppable. It proved to be an accurate name for the event, as Silva has never looked back, owning the Octagon for the past four years as he has built a UFC record 10-fight winning streak, and finished nine of ten opponents in the process.

Lyoto Machida, 8-0. "The Dragon" stands at a perfect 16-0 in his career, and half of those wins have come inside the Octagon. The light-heavyweight champ holds notable UFC wins over Tito Ortiz, Thiago Silva, Rashad Evans, and Mauricio "Shogun" Rua, though his recent title defense against Rua came by way of a very controversial unanimous decision.

Jon Fitch, 8-0. Fitch got off to a then-record 8-0 start in the UFC, including wins over Thiago Alves and Diego Sanchez, before earning a title shot against welterweight champ, Georges St. Pierre. Unfortunately for Fitch the Canadian phenom would end his perfect UFC record, but not before Fitch had gone the distance in an exciting five-round war.

Randy Couture, 7-0. "The Natural" began his UFC career with a dominant heavyweight performance that spanned seven fights, and victories over opponents which included Vitor Belfort, Kevin Randleman, and Pedro Rizzo. Couture went on to hold both the heavyweight and light-heavyweight belts and eventually earned a place in the UFC Hall of Fame. Couture's record start stood for nearly seven years, until Fitch passed the mark in 2008.

Rich Franklin, 7-0. Franklin showed us all just how tough a math teacher can be when he began his MMA career in 1999.  "Ace" took the UFC middleweight title from Evan Tanner at UFC 53, one fight after stopping MMA legend Ken Shamrock with a first-round TKO in a light-heavyweight bout. Franklin's unbeaten UFC run ended at UFC 64 when Anderson Silva became just the second man to defeat him in more than 20 career fights.

Diego Sanchez, 6-0.  "The Nightmare" followed up his victory over Kenny Florian on "The Ultimate Fighter" season 1 finale with an impressive string of Octagon wins. Sanchez's run included victories over Nick Diaz and Karo Parisyan before he finally came up up short in a decision loss to Josh Koscheck at UFC 69.

Cain Velasquez, 6-0. Velasquez has gotten off to a red-hot start in his UFC career,...