Ryon Healy broke the tie when he hit a hard shot that shortstop Ian Sagdal couldn't handle allowing Brett Thomas to score from second. After Mitchell Tolman walked to load the bases, Aaron Payne scored on an unusual fielder's choice RBI by Scott Heineman to give the Ducks a 5-3 lead.
Heineman's hit would have been a single, but left fielder Trek Stemp made a diving attempt that forced Healy back to second base briefly. Stemp grabbed the ball and threw to pitcher J.D. Leckenby covering third to get Healy on a 7-1 force out.
Mitchell Tolman gave Oregon an early 3-0 lead. The freshman drove in the Duck's first run with a bunt single in the first inning and added a two-RBI single in the third inning. Tolman's three runs batted in gave him 12 in Oregon's last three games.
Oregon's bullpen shut the door on the Cougars the rest of the way with Darrell Hunter, Cleavinger and Sherfy retiring all eight batters they faced, five on strikeouts.
Tolman went 2-for-3 with three RBI to lead Oregon (35-11, 17-5 Pac-12), while Thomas was 4-for-5 with two runs scored. Payne went 2-for-3 with three runs scored.
The Ducks and Cougars will play game two of the three-game series Saturday at 2 p.m.