Carper and Chandler both went 3-for-4.
Sammamish moves into the winner's bracket and won't have to play again until Sunday against the winner of the game between Nashville, Tenn., and Wesport, Conn.
Corpus Christi will play the loser of that game Saturday, facing elimination.
Sammanish scored four times in the top of the first.
A single by Oscar Hernandez of Corpus Christi scored Brandon DeLeon during a three-run third inning to cut the lead to 5-4.
Washington relievers Will Armbruester and Jack Matheson blanked Texas over the final three innings.