UFC 57: Liddell vs. Couture 3 was a mixed martial arts event held by the Ultimate Fighting Championship on February 4, 2006. It was held at the Mandalay Bay Events Center on the Las Vegas Strip in Nevada, and broadcast live on pay-per-view in the United States.

Headlining the card was an anticipated rubber match between top UFC stars and former coaches of The Ultimate Fighter Chuck Liddell and Randy Couture, widely touted and marketed as MMA's first major trilogy.

It was the UFC's largest grossing gate to date, $3.3 million , in addition to an estimate of over 400,000 pay-per-view buys. The disclosed fighter payroll for the event was $667,000.

Diego J. Sanchez (born December 31, 1981) is an American mixed martial artist (MMA) of Mexican descent, with a background in wrestling and Gaidojutsu, system of submission wrestling developed by his longtime trainer Greg Jackson. He currently fights as a welterweight with the Ultimate Fighting Championship (UFC). Sanchez is currently ranked as the #9 welterweight fighter in the world by MMAWeekly.

Sanchez was born in Albuquerque, New Mexico. He attended Del Norte High School, where he became a state champion wrestler.^{[citation needed]}

Diego Sanchez wrestled in New Mexico before starting training MMA while working for UPS. Sanchez eventually joined Jackson's Submission Fighting, still while working for UPS, managing the time between work and training. In 2002, he made his MMA debut for King of the Cage where he also later became a champion.

His UFC debut came when he was chosen as a participant on the first season of the reality show, The Ultimate Fighter. Presented as a young, focused middleweight who only had one goal, to become a UFC champion, he won a contract with the UFC after winning a fight against Kenny Florian, becoming the middleweight winner for the first season of the show. On the show, Sanchez was known for being the "odd-ball" of the group, practicing yoga at odd moments and trying to extract "energy" from a lightning storm, and was also a self-proclaimed "Zen master". Sanchez' last fight before his loss to Josh Koscheck was against Joe Riggs on December 13, 2006 at UFC Fight Night 7. Sanchez landed a right hook that knocked Riggs down, followed by a running knee that knocked Riggs out. Sanchez won at 1:45 of the first round, scoring the first UFC knockout of his career.

Renato da Cunha Sobral (Portuguese pronunciation: [ʁeˈnatu soˈbɾaw]; born September 7, 1975), also known as "Babalu", is a Brazilian mixed martial artist, and former Strikeforce Light Heavyweight Champion. He is noted for holding on to chokes for too long. Sobral previously fought in the Ultimate Fighting Championship, where he posted a 6–4 record. He is a member of the Gracie Barra Cerritos and has a Brazilian Jiu-Jitsu black belt under Carlos Gracie Jr. Some of his MMA achievements include defeating fighters Trevor Prangley, Maurício Rua, and Jeremy Horn in a single night at IFC's Global Domination tournament. Sobral also holds wins over Chael Sonnen, Robbie Lawler, and Cyrille Diabaté.

Sobral's background is in wrestling. Before joining the Gracie Barra Combat Team he was a Brazilian national wrestling champion and was trained in Ruas Vale Tudo, a martial arts system developed by Marco Ruas.

At UFC 62, Sobral was defeated by Chuck Liddell in a bout for the UFC Light Heavyweight Championship. The match was stopped as a technical knockout at 95 seconds into the first round. Following his loss to Liddell, Sobral faced Jason Lambert at UFC 68. Sobral was knocked out in the second round.

Dana White (born July 28, 1969) is the current President of the Ultimate Fighting Championship (UFC), a mixed martial arts organization based in the United States.

Born in Manchester, Connecticut on July 28, 1969, White grew up in Las Vegas, Nevada, Ware, Massachusetts and Levant, Maine. White is a passionate Boston Red Sox fan. During his youth, he bounced back and forth between Boston and Maine. He attended the University of Massachusetts Boston but did not finish; however, while there he did launch a boxing program for inner-city youth.

White has a background as an aerobics instructor. In 1992, White established Dana White Enterprises in Las Vegas. He conducted aerobics classes at three gyms in the Las Vegas area and began managing MMA fighters Tito Ortiz and Chuck Liddell.

While working as a manager, White learned that Semaphore Entertainment Group, the parent company of the UFC, was looking for a buyer for the UFC. White contacted childhood friend Lorenzo Fertitta, an executive at Station Casinos, and a former commissioner of the Nevada State Athletic Commission. Within a month, Lorenzo and his older brother Frank bought the UFC, with White installed as its president. White currently owns about 9% of Zuffa, LLC, the entity the Fertitta brothers created to own and manage the UFC.

Gilbert Q. Melendez (born April 12, 1982) is an American mixed martial artist of Mexican descent currently fighting out of San Francisco, California, he is the current Strikeforce Lightweight Champion fighting in the lightweight division for Strikeforce.

He formerly competed in the lightweight division of PRIDE Fighting Championships. He has trained extensively with Turbo Fairtex, Jake Shields, Cesar Gracie, Nick Diaz, Nate Diaz and David Terrell. Melendez is the Strikeforce Lightweight Champion and has avenged both his career losses. Melendez is ranked as the #3 lightweight fighter in the world by Sherdog.

Melendez aka El Nino began fighting in the pre-Zuffa World Extreme Cagefighting and Rumble on the Rock shows and also spent some time overseas where he fought for Shooto and PRIDE Fighting Championships

Melendez won the Strikeforce Lightweight Championship from Clay Guida by split decision on June 9, 2006.

Melendez held the belt for two years before losing it on June 27, 2008 to Josh Thomson by unanimous decision (50–45, 50–45, 50–45) at Strikeforce: Melendez vs. Thomson.