Zab Judah is the new undisputed welterweight champion of the world. Judah, knocked out St. Louis native Cory Spinks in the ninth round to claim the title. Referee Armando Garcia stepped in at 2:49 of the ninth round after Spinks survived one knockdown earlier in the round. Judah improved to 33-2 with 24 wins inside the distance and avenged a loss by unanimous decision to Spinks last April. Spinks, who was defending the World Boxing Council, World Boxing Association and International Boxing Federation belts before an enthusiastic home crowd of more than 22,000 at the Savvis Center, fell to 34-3. A straight left from Judah marked the beginning of the end for Spinks in the ninth. Shortly after it landed Spinks went down amid a barrage of blows. Spinks, son of former heavyweight world champion Leon Spinks and nephew of former champion Michael Spinks, had won his previous five fights.