Osvaldo Alonso set up Eddie Johnson's goal in the 31st minute, then converted a penalty kick just two minutes into the second half and the Seattle Sounders beat Chivas USA 4-1 Wednesday night in a U.S. Open Cup semifinal game.

Brad Evans (83rd minute) and Sammy Ochoa (88th) also scored for the Sounders, who will go for an unprecedented fourth straight Open Cup title when they visit Sporting Kansas City on Aug. 8.

Sporting earned its spot in the final on Wednesday with a 2-0 road victory against the Philadelphia Union.

Second-half sub Cesar Romero scored on a rebound of his own shot early in the 74th minute for Chivas USA. The Goats were seeking their first spot in the final, but lost to the Sounders in the semis for the second time in three years.

Seattle has not lost an Open Cup game since joining Major League Soccer in 2009, putting together a 17-0-1 record. That includes title game victories at D.C. United in 2009, and at home against Columbus in 2010 and Chicago in 2011.