D.C. United vs.

Philadelphia Union

What: U.S. Open Cup round of 16. The tournament, celebrating its 100th year, involves teams from all levels of American soccer.

Where: Maryland SoccerPlex, Boyds.

When: 7 p.m.

Tickets: $20 ($10 for season ticket holders). Kids under 16 are admitted free if accompanied by an adult.

Outlook: United is 1-10-3 in MLS play and carrying a club-record 12-game winless streak. Its overall skid is 13, counting a 0-0 draw with the third-division Richmond Kickers in the previous Open Cup game May 28. (United advanced in a penalty kick tiebreaker.) Philadelphia, which ousted fourth-level Ocean City (N.J.) two weeks ago, is 6-5-4 in league play. United D Chris Korb and F Carlos Ruiz are serving suspensions after receiving red cards against Richmond. Swiss D Alain Rochat, acquired by United from the Vancouver Whitecaps last week, is not eligible to play in the Open Cup until the semifinals because his international transfer certificate won’t switch from Canadian to American soccer affiliation until next month. He is eligible, however, to play in MLS matches, starting Saturday against Toronto FC at RFK Stadium. The winner of the United-Union match will host the New York Red Bulls or New England Revolution in a June 26 quarterfinal. If D.C. advances, it would utilize the SoccerPlex again. Last year, Philadelphia eliminated United in the round of 16, 2-1, in overtime. The teams have a history of contentious matches and have already met three times this year: twice in preseason in Florida and once in the regular season (a 3-2 Union victory April 21 in Washington). “I don't know why our guys get like this,” Union Coach John Hackworth said of the animosity. He and United coach Ben Olsen “get along just fine."

— Steven Goff