that Ortiz was his toughest opponent physically due to his weight advantage and style of fighting. With this win, Shamrock solidified himself as perhaps the greatest UFC champion in history to that date, going 5–0 in title fights and finishing each fight decisively. After the win, UFC owner Bob Meyrowitz and announcer Jeff Blatnick both praised Shamrock as the greatest competitor in the history of the UFC. Shamrock then relinquished his title and retired from the UFC. After retiring, he briefly acted as a consultant and commentator for the company. In an interview, UFC president Dana White said: I've talked to Frank Shamrock many times. Frank Shamrock will lead you to believe that we've never talked and we completely have hated each other forever and everything else. He's a weird guy. He's a very, very weird guy. I can't explain it. Frank is a weird guy. Return After a brief retirement, Shamrock returned to mixed martial arts as a career. He signed a deal to fight Brazilian Jiu-Jitsu standout Elvis Sinosic at K-1, the premiere kickboxing event in the world. Shamrock beat Sinosic via unanimous decision after five three-minute rounds. Later, when Sinosic faced Tito Ortiz for the UFC light-heavyweight title (formerly the middleweight title) at UFC 32, Shamrock served as guest commentator. On August 11, 2001, he took on his former student, Shannon Ritch in a kickboxing match for K-1. Just 56 seconds into the first round, Shamrock broke Ritch's arm with a roundhouse kick and thereby won the match. Shamrock helped to train UFC veteran B.J. Penn for his early bouts with the UFC at the American Kickboxing Academy and produced his own events Bushido and ShootBox. His first MMA match since 1999 was winning the WEC light-heavyweight championship in under two minutes from Bryan Pardoe by submission in March 2003. On March 10, 2006, at Strikeforce: Shamrock vs. Gracie, the first MMA event sanctioned by the state of California, he knocked out Cesar Gracie in 21 seconds. Gracie had never fought an MMA match and was 40 years old, so the fight was considered a serious mismatch. However, Gracie is an elite Brazilian Jiu-Jitsu instructor with years of training under his belt as well being the mentor of students such as the Diaz brothers, Nate and Nick. On September 14, 2006, it was announced that Shamrock had signed a multimillion-dollar contract with startup MMA organization "The World