UFC 6: Clash of the Titans was the sixth mixed martial arts event held by the Ultimate Fighting Championship on July 14, 1995, at the Casper Events Center in Casper, Wyoming. The event was seen live on pay per view in the United States, and later released on home video.

UFC 6 featured the crowning of the first UFC Champion to win the title in a non-tournament format. The champion would be the winner of a special match called 'The Superfight', which continued from UFC 5 as there was no official winner in the previous Superfight. UFC 6 also featured an eight-man tournament, and two alternate fights which were not shown on the live pay-per-view broadcast. The tournament had no weight classes, or weight limits. Each match had no rounds; therefore no judges were used for the night. A 20 minute time limit was imposed for the quarterfinal and semi-final round matches in the tournament. The finals of the tournament and the Superfight had a 30 minute time limit and, if necessary, a five minute overtime.

Nicholas Robert Diaz (born August 2, 1983) is a American mixed martial artist of Mexican descent. He is the former Strikeforce Welterweight Champion, WEC and IFC Welterweight Champion. He has competed in the Ultimate Fighting Championship, Pride Fighting Championships and Elite Xtreme Combat. Diaz was promoted to black belt in Brazilian Jiu-Jitsu by Cesar Gracie on May 8, 2007. Diaz trains at the Diaz brother's Cesar Gracie Jiu-Jitsu Academy in Lodi, California. Diaz holds the distinction of having never been submitted, and has been finished by strikes only once in 35 fights. He is currently ranked the #4 welterweight in the world by Sherdog, ESPN, MMAWeekly, and USA Today.

Diaz was born in Stockton , California. He is the older brother of UFC fighter Nate Diaz. He went to Tokay High School in Lodi for one year before dropping out. While a freshman, he was a member of the swimming team. Diaz has stated in the past that he is thankful his mother got him into swimming classes because swimming is one of the main reasons why his cardio is so impressive during his fights. Diaz has also said on multiple occasions that he had a hard childhood and grew up without his biological father.

Ronda Rousey (born February 1, 1987) is an American judoka and mixed martial artist and the current Strikeforce Women's Bantamweight Champion. She has finished all of her opponents by armbar in the first round. She formerly trained at the Olympic Training Center in Wakefield, Massachusetts under guidance of Jimmy Pedro and is now part of Team Hayastan in Santa Monica, California.

Rousey trains under Gokor Chivichyan and Edmond Tarverdyan of the Glendale Fighting Club in Glendale, CA. Rousey also trains with Leo Frincu and Gene Lebell, along with Team Hayastan fighters such as Manny Gamburyan, Karen Darabedyan, Sako Chivitchian and Sevak Magakian. She is managed by Darin Harvey of Fight Tribe MMA.

Rousey is currently the #1-ranked pound-for-pound female MMA fighter in the world by MMARising.com, and is ranked #1 at 135 pounds and #2 at 145 pounds according to the Unified Women's MMA Rankings.

At just 17, Rousey qualified for the 2004 Olympic Games in Athens, becoming the youngest judo player in the entire Games. Also in 2004, Rousey won a gold medal at the 2004 World Junior Judo Championships in Budapest, Hungary.

Anthony Pettis (born January 27, 1987) is an American mixed martial artist who competes in the lightweight division and is currently signed with the Ultimate Fighting Championship. A professional MMA competitor since 2007, Pettis has made a name for himself mainly fighting in his home state of Wisconsin. He is a former fighter for the World Extreme Cagefighting (WEC), where he was the last WEC Lightweight Champion before merging the promotion into the UFC.

Born to Eugene Pettis Jr. and Annette Garcia, Anthony Pettis grew up in the south side of Milwaukee, Wisconsin along with his older brother Ray Pettis and younger brother Sergio "Lil' Showtime" Pettis. Pettis is of Mexican and Puerto Rican ancestry, his grandfather Anglicized the family name from Perez to Pettis, to avoid discrimination. Pettis attended Dominican High School.

Anthony "Showtime" Pettis made his professional MMA debut in December 2007. He compiled an undefeated record of 8-0 in shows all based in Milwaukee, Wisconsin before debuting with the WEC. Pettis also has a professional kickboxing background.

Ricardo Alejandro Lamas (born May 21, 1982) is an American mixed martial artist who currently fights as a featherweight in the Ultimate Fighting Championship organization. He trains with Team Top Notch in Elmhurst, Illinois. Lamas currently holds a brown belt in Brazilian Jiu-Jitsu under 2007 World Nogi jiu jitsu champion Daniel Valverde.

Lamas' father is Cuban and his mother is Mexican. The flags of these two countries are often displayed on his clothing during his fights.

Lamas graduated with a degree in exercise science from Elmhurst College in 2005, where he was a member of the men's wrestling team and earned All-American honors at the NCAA Division III Men's Wrestling Championships at 157 lbs. During his collegiate wrestling career (2001–2005), he racked up over 100 wins. He was also a two-time CCIW Champion, and was named the CCIW's "Most Outstanding Wrestler" during the 2003-04 season. Lamas returned to Elmhurst after graduation to serve as the assistant men's wrestling coach.

On March 1, 2009, Lamas made his WEC debut at WEC 39 in Corpus Christi, Texas against IFL and WEC veteran Bart Palaszewski. Lamas took the fight with 4 days notice. Lamas controlled Palaszewski with superior wrestling and scored with excellent ground-and-pound to win a unanimous decision victory over the more experienced fighter. Lamas suffered his first loss against Danny Castillo at WEC 42 on August 9, 2009.