After his successful amateur wrestling career at Bismarck State College and the University of Minnesota, Lesnar signed with WWE (then the World Wrestling Federation) in 2000. He was assigned to its developmental promotion Ohio Valley Wrestling (OVW), where he was a three-time OVW Southern Tag Team Champion with Shelton Benjamin. After debuting on WWE's main roster in 2002, Lesnar won the WWE Championship[Note 1] five months after his debut at the age of 25, becoming the youngest champion in the title's history. Following his match with Bill Goldberg at WrestleMania XX, Lesnar left WWE and pursued a career in the National Football League (NFL). He was named a defensive tackle for the Minnesota Vikings, but was cut prior to the start of the 2004 season. In 2005, Lesnar returned to professional wrestling and signed with New Japan Pro-Wrestling (NJPW), where he won the IWGP Heavyweight Championship in his first match. After a contractual dispute with NJPW, he also wrestled as IWGP Heavyweight Champion in the Inoki Genome Federation (IGF).