Kenyon Yovan's three-run home run in the first inning resulted in the only runs for Oregon.
Trevor Larnach followed with a homer in the second inning that got Oregon State started on offense.
The sixth-ranked Beavers (33-7) scored twice in the second and fourth innings to defeat the Ducks 4-3 in a nonconference game in front of 1,772 Tuesday night at PK Park.
After Jordan Britton gave up three runs in the first inning, OSU brought freshman Kevin Abel out of the bullpen for 6 1/3 scoreless innings. Gabe Matthews' single in the fourth inning was the second and final hit for the Ducks (21-21).
"Tip your cap to Abel because in a midweek game, you don't expect a guy to give you six innings and allow one hit," UO coach George Horton said of the right-hander who entered the game with a 5.72 ERA. "He was outstanding. He kept us off balance and we didn't put much pressure on them after the home run."
Oregon's Jonny DeLuca reached first on an error in the first inning and Kyle Kasser was hit by a pitch before Yovan hit a homer to left with two outs.
After UO starter James Acuna retired the Beavers in order in the first inning, Larnach opened the second with a home run. Acuna walked the next two batters and hit Michael Gretler to load the bases before walking Troy Claunch to bring in a run.
"The difference in the game is what they did after their homer versus what we did after ours," Horton said. "They retired the next eight batters and we walked two, hit a batter, and walked another guy. ... I don't know what happened to (Acuna) when he got punched in the nose by the Larnach homer. All of a sudden, he lost it there for a bit."
Tyler Malone walked to open the fourth inning and Jack Anderson followed with a single. Claunch hit a one-out double to right that scored Malone with the tying run.
Steven Kwan followed with a grounder that scored Anderson to put the Beavers into the lead.
Yovan was hit by a pitch with one out in the fourth and Matthews followed with a single before Ray Soderman grounded into a double play. Jakob Goldfarb walked in the fifth inning and Kasser walked in the sixth, but both were caught stealing.
"We couldn't get much offense and then we try a stolen base and they throw us out and try a hit-and-run and they guessed right and got us on that one," Horton said. "We were trying to make something happen. They are tough to score on when they throw strikes and obviously they play very good defense."
Abel retired the final five batters he faced before closer Jake Mulholland retired the last five Ducks to earn the save.
Acuna gave up three hits and four runs in four innings before being relieved by Cullen Kafka, who allowed two hits in 2 2/3 scoreless innings. Parker Kelly held the Beavers scoreless for the final 2 1/3 innings as Oregon State finished with six hits while beating the Ducks for the fourth time in 13 days.
"You have to be opportunistic," Horton said. "It reminds me of playoff baseball where both teams know a lot about each other and the hitters. If pitchers can execute, you are going to see good pitching because of the familiarity with the two clubs."