D.C. United is an American professional soccer club based in Washington, D.C., which competes in Major League Soccer. It is one of the ten charter clubs of MLS, having competed in the league since its inception, in 1996. D.C. United has won 13 international and domestic titles or honors over the club's history. D.C. United was one of the most successful clubs in the early years of MLS, winning 8 of its 13 titles between 1996 and 1998 under head coach Bruce Arena. United holds the joint MLS record for most Supporters' Shields, and has had success in the MLS Cup, winning each honor four times along with three U.S. Open Cup championships. United was also the first club to win both the MLS Cup and MLS Supporters' Shield consecutively. On the international stage, D.C. United has competed in both the CONCACAF Champions League and its predecessor, the CONCACAF Champions' Cup. The club participated in the 2005 and 2007 editions of the Copa Sudamericana. In 1998, the club won the CONCACAF Champions' Cup. Subsequently, United won the now-defunct Copa Interamericana, a CONCACAF-CONMEBOL super cup, in 1998 against Vasco da Gama of Brazil. The team's home field is the 45,596-seat Robert F.