 On April 12, 1996, Phillips made his first world title challenge by facing WBA welterweight champion Ike Quartey, but was stopped in three rounds.A year later, on May 31, 1997, he scored a major upset by defeating then-unbeaten world champion Kostya Tszyu to win the IBF junior welterweight title, which was named the Upset of the Year by "The Ring" magazine.Phillips made three successful title defenses throughout 1997 and 1998, until a fifth-round stoppage loss to Terron Millett on February 20, 1999.