Sophomore right-hander Mike Leake earned his second win of the postseason, allowing four runs -- two earned -- and eight hits over 7 2-3 innings. Leake struck out two and walked one.
Sontag broke a 1-1 tie in the bottom of the third with a towering home run over the right-field fence.
Fresno State (40-29) scored once in the seventh and pulled within 8-4 in the eighth on Alan Ahmady's two-run single to right.
Junior left-hander Justin Wilson took the loss for the Bulldogs, allowing eight runs -- six earned -- and nine hits with two walks and five strikeouts in 4 1-3 innings.