D.C. United, Houston, and expansion Seattle advanced to the semifinal round and join USL-1 Rochester, which knocked out USL-2 Wilmington, 2-1, on Tuesday
Boyzzz Khumalo and Andrew Jacobson scored in the first half for a 2-0 D.C. lead against USL-2 Harrisburg, which went down to 10 men following the dismissal of captain Mo Oduor early in the second half when he elbowed John DiRaimondo in the face. Rather than folding, the City Islanders struck with a goal by Nicki Paterson in the 64th minute and threatened several times to equalize, including a David Schofield shot that clanged off the United crossbar, before succumbing.
United plays Rochester, the last non-MLS team to win the Open Cup, in the semifinals July 21 at the Maryland SoccerPlex in Boyds, Md.
Houston turned the tables on Charleston, which had eliminated it from the Open Cup the past two years, by rolling to a 4-0 win at Blackbaud Stadium.
Geoff Cameron had two goals, John Michael Hayden picked up two assists, and Bobby Boswell and Dominic Oduro also scored to earn a spot in the semifinals against Seattle, which edged past Kansas City, 1-0, with a Sebastian LeToux penalty kick in the 89th minute.
Charleston sent the Dynamo out of the tournament in 2007 with an overtime penalty kick and in a penalty-kick shootout last year.
"It's very disappointing, especially considering we've made it to the semifinals the last two years," said Charleston head coach Mike Anhaeuser. "Now we put it behind us and concentrate on league play."
The Battery took over first place in the USL First Division by beating Montreal, 1-0, Sunday.
Seattle will host Houston in the semifinals July 21 or 22 at the Starfire Sports Stadium in Tukwila, Wash.
July 7 in Tukwila, Wash.
Seattle Sounders FC 1, Kansas City Wizards 0. Goal: LeToux (penalty kick) 89.
Seattle - Keller, Ianni, Wahl, Riley, Hurtado, Sturgis (Vagenas, 91+), King, Zakuani (LeToux, 71), Nyassi (Levesque, 78), Jaqua, Montero.
Kansas City - Hartman, Besler, McKenzie, Holbein, Leathers (Watson, 46), Hirsig, Harrington, Jewsbury, Gomez, Wolff, Thompson (Lopez, 70).
Red card: Kansas City -- Hirsig 93+.
Referee: Abiodun Okulaja
July 7 in Charleston, S.C.
Charleston Battery 0, Houston Dynamo 4. Goals: Cameron (Hayden) 16, Boswell (Hayden) 47, Oduro 52, Cameron (Mullan) 73.
Charleston -- Hudock, Sanfilippo, Bobo (Antoniuk 59), Akwari, Wilson, Williams (Yoshitake 59), Treschuk, Hemming (Armstrong 64), Buete, Spicer, Patterson.
Houston - Hall, Chabala, Boswell, James, Cruz (Davis 81), Hayden, Ustruck, Cameron, Ashe (Mullan 45), Akinbiyi, Oduro (Kamara 61).
Referee: Tony Russo.
July 7 in Boyds, Md.
D.C. United 2, Harrisburg City Islanders 1. Goals: Khumalo (McTavish) 8, Jacobson (Fred) 18; Paterson 64.
D.C. United - Kocic, John, Janicki, McTavish, Namoff (Gomez, 71), DiRaimondo, Fred, Barklage (Wallace, 29), Jacobson, Khumalo, N'Silu.
Harrisburg - Harrison, Baker, Bloes, Velten, Calvano (Kasiguran, 81), Fisher (Swartzendruber, 65), Paterson, Shipalane, Oduor, Severs (Schofield, 61), Pelletier.
Red card: Harrisburg -- Oduor 49.
Referee: Lee Suckle.
July 7 in Wilmington, N.C.
Wilmington Hammerheads 1 Rochester Rhinos 2. Goals: Atieno (Ambersley) 54, Gregor (pen.) 67; Watson 72.
Wilmington -- Polak, Falvey, Walters, Thayer, Tatters, Briggs (Franks 79), Bundy, Dombrowski, Solle (Murray 67), Hufstader (Bagley 65), Watson.
Rochester -- Melia, Bertz, Ball, Earls, Harden, Heins, Gregor, Ambersley Sarkodie 81), Short (Fitzpatrick 45), Menyongar, Atieno.
Referee: Niko Bratsis.