Anson Dorrance won his 500th game after losing one of his top forwards, and the ranks of the unbeaten in Division I college women’s soccer dropped by one during action Thursday night. Dorrance, whose North Carolina teams have won 17 national championships in 20 years, notched win No. 500 as his top-ranked Tar Heels toppled No. 13 Clemson before 1,325 at Fetzer Field in Chapel Hill, N.C. News that forward Susan Bush would miss the remainder of the season doused the celebration. Across the continent, No. 2 UCLA dropped its first game of the season, falling to third-ranked Santa Clara, 3-0, at the Broncos’ Buck Shaw Stadium. Freshman Anne Morrell scored in the third minute and Anne Remy netted a pair for Carolina (13-0), which outshot the Tigers, 29-3. UNC is 5-0 in Atlantic Coast Conference play; Clemson fell 9-3 overall, 3-3 in ACC action. Dorrance, in his 23rd year as Tar Heels women’s coach, becomes the third Division I coach — and first Division I women’s coach — to win 500 matches. San Francisco’s Stephen Negoesco won 544 games in 39 years as the Dons’ men’s coach, and Indiana’s Jerry Yeagley has captured 503 since 1973 with the Hoosier men. Dorrance’s record with the UNC women is 500-22-11. He also notched a 172-65-21 mark with Carolina’s men’s team from 1977 through 1988. His combined record is 672-87-32. A test earlier Thursday determined that Bush, a junior forward who had debuted for the U.S. women’s team while still in high school, had suffered a torn anterior cruciate ligament in her left knee during Carolina’s victory last week over Florida State. Bush missed the last part of the 2000 season after sustaining a torn ACL in late October. In Santa Clara, Aly Wagner scored her 11th and 12 goals of the season — bending home a corner kick with the second — and assisted on Danielle Slaton’s seventh-minute winner as the Broncos (12-1) hammered the visiting Bruins (11-1). The win, notched before a crowd that included WUSA coaches Jay Hoffman (Boston Breakers), Patrick Farmer (New York Power) and Carlos Juarez (San Diego Spirit), was the 231st for Coach Jerry Smith. Santa Clara takes on another unbeaten team on Sunday, when it travels to nearby Moraga for a West Coast Conference showdown with St. Mary’s (11-0-1). The Gaels first face the nation’s third remaining unbeaten squad, Pepperdine (8-0-3), Friday afternoon in a WCC game in Moraga. Carolina will get perhaps its toughest test of the season on Saturday afternoon when it stages its alumni game at Fetzer.