This is it," exulted John Dueker. "You can feel no more. There is no more to feel." Dueker plays on the St. Louis University soccer team. It was the first NCAA soccer championship, which the undefeated Billikens had just won by defeating the University of Bridgeport 5-2 on a day so powerfully wrought with wind and rain that the score was kept inside a plastic bag. Dueker had plenty to crow about. This is the first year soccer has been a varsity sport at St. Louis, the team is composed entirely of St. Louisans (semifinalist CCNY has 14 foreign-born players on a roster of 16), the team budget was $200, the players had to kick in for their shoes and Coach Bob Guelker volunteered his services. A good thing: he was the only one who owned a ball.