CORVALLIS - Oregon State, ranked 19th in the nation, knocked off No. 5 Arizona State 5-3 on Friday night.
A crowd of 2,547 at Goss Stadium saw the series opener. Game 2 is 1 p.m. Saturday, with the finale at 1 p.m. Sunday.
OSU trailed 2-1 before scoring four runs (all with two out) in the seventh inning - with Ryan Dunn driving in Jared Norris and Kavin Keyes from second and first base, respectively, with a bloop double down the left-field line.
Sam Gaviglio (6-1) pitched his third complete game of the season to earn the win. He allowed nine hits and one walk, while striking out six batters.
Dunn, Keyes, Norris and Tyler Smith all had two hits for the Beavers.
Brian Stamps, a defensive replacement, preserved the OSU lead with a big third-out catch in center field in the eighth inning.
Oregon State won its fourth straight game and climbed to 22-7 overall, 3-1 in the Pac-10.
ASU dropped to 22-7, 5-2.