D.C. Unite is a professional soccer club located in Washington, D.C. that participates in Major League Soccer, the United States' top-tier soccer league. Considered the most successful club in American soccer, the club has won the U.S. Open Cup and holds the record for most MLS Cups and MLS Supporters' Shields with four apiece. Furthermore, D.C. United is the only club to be awarded the MLS Supporters' Shield back-to-back (2006 and 2007) and the first club to win back-to-back MLS Cups (1996 and 1997). In 1998 D.C. United became the first American club to win the CONCACAF Champions' Cup and the Copa Interamericana, defeating Club Toluca of Mexico 1-0 and Vasco da Gama of Brazil on 2-1 aggregate.