Jesse O'Hagan singled to lead off the eighth and was replaced by pinch-runner Braeden Jacobsen, who was moved into scoring position on a bunt by Mikey Schmidt.
"It's a tough game to play in," Coeur d'Alene coach Nick Rook said. "The kids did a good job today and really enjoyed themselves. It was good to come out with a win."
Schmidt pitched the final two innings for Coeur d'Alene (24-3) and picked up the win, tying the school record for wins in a season with 10. Jake Pereira won 10 in 2011.
Lewiston finished 12-14.
It was Coeur d'Alene's fourth straight trip to state, and the third straight year the Vikings brought home a trophy. Coeur d'Alene tied for third in 2010, and won the consolation title last year.
Lewiston 102 001 20 - 6 8 0
Coeur d'Alene 040 020 01 - 7 8 0
Aaron Kracke, Trevor Ralstin (6) and Tyler Charlo; Ransom Storm, Mark Nuttleman (6), Mikey Schmidt and Levi Pereira. W - Schmidt (10-1). L - Ralstin.
HITS: Lew - Fuller 3, Ralstin, Tibbits, Brooks, McMinn, Charlo. Cd'A - Roletto 2, S. Sutton, Duran, DeHaas 2, O'Hagan, Nyquist. 2B - Roletto, Duran.