The Lady Noles (22-11), who also won the fastpitch state title in May, blanked West Union in the first game 7-0 and scored early and held on late in the second game with an 8-5 win.
"We had a play to end the sixth inning and leave the bases loaded," Smithville coach Jeremy Duke said. "We didn't want to get deep in their lineup right there and have to go back through the top of their order in the seventh."
Smithville pitcher Ashtyn Hensley held West Union to four hits in the first game, while going 2 for 3 at the plate.
Back-to-back doubles by Laken Armstrong and Morgan Barrett and a sac fly from Katie Beth Williams put the Lady Noles on the board in the second. They added three in the third with a two-run single from Claire McNeese and a bases-loaded walk to Barrett and padded their lead with two more in the fourth. Hensley and Breanna Edgeworth knocked in runs on singles. Lone senior Kyla Ford went 8 for 8 with two RBIs.
The second game saw Smithville get out to a quick 7-0 lead after a five-run first. Edgeworth had an RBI single, but the big hit of the game came on Armstrong's three-run homer to dead center.
Down 8-0, the Lady Eagles chipped away at the deficit, scoring two in the second and three in the sixth. In the sixth, Gina Beth Conlee's two-run single and Jodie McMillen's RBI single brought West Union to within three before Angel Guyton fired to second to end the inning after a hit from Callie Baggett.
"When you don't hit, you can't win, and we didn't hit today," West Union coach Lisa Bogue said.
Smithville will go after its third state title in the last five years on Saturday.
"We hit good today, well enough to win. We know we have our work cut out for us at state, though," Duke said.