Oregon got on the board with a two-out RBI double by catcher Jack Kruger in the second, before turning Wheatley's day into a nightmare with a four-run third inning.
Led by a Mitchell Tolman two-run double and A.J. Balta's two-out, two-run home run to right field, the Ducks chased the senior, who gave up a season high five earned runs on seven hits in a season low three innings.
"I thought we were locked in," UO head coach George Horton said. "We challenged our guys that they're going to have to recognize the wiggle in Wheatley and how he pitches. He's not a guy that just blows you away with stuff."
Right-hander Brooks Kriske came on to relive Wheatley but couldn't stop the bleeding. He gave up a two-out, two-run ground rule double to Tolman with the bases loaded in the fourth, pushing the Ducks lead to 7-0, a season high allowed by the Trojans (10-7, 7-1).
Tolman finished the day going 2-for-5 with four RBI and a run scored, making him the first Duck to reach 20 RBI this season.
"There's certain series' or hitters that you just don't want to see get in the batters box and Mitch certainly has the look in his eye," Horton said of Tolman's play as of late.
Oregon freshman Matt Krook, making his first Pac-12 start, earned his first collegiate victory on Saturday. The conference leader in strikeouts added six more to his total in six-plus innings, giving up two hits and two earned runs that scored after he exited in the seventh inning.
All four of Krook's walks came in the sixth and seventh innings, following a dominant stretch where he retired 10 consecutive Trojan batters.
"I got more confident as the game went on," Krook said. "I talked with coach about something mechanically after the second inning and it just clicked."
The second inning could've turned into a completely different ballgame when Krook found himself in a jam with runners on second and third and no outs, but the defense picked him up.
Krook induced two grounders to Tolman, the latter starting a wild double play that saw Trojans right fielder A.J. Ramirez tagged out in a rundown between third and home and second baseman Dante Flores tagged out trying to sneak second base on the fielder's choice to end the threat.
Krook (1-1) called it "the play of the game", and from that point on he was almost un-hittable.
"It was huge," Krook said of the double play. "It gave me a lot of energy. I thought it brought a lot of momentum to our team and once we got the runs, I was just trying to throw a first pitch strike and trying to eliminate pitches."
After Krook exited with one out in the seventh, freshman right-hander Stephen Nogosek came on, but never really settled in before handing the ball over to Trent Paddon with two on and one out in the eighth.
Paddon quickly struck out Jeff Paschke and Kyle Davis to end the Trojan threat. The Ducks turned a 4-6-3 double play to start the ninth before Tyler Baumgartner, who had a critical error in Friday's game, made a diving catch in right to end the game.
The Ducks and Trojans face off in a rubber match tomorrow at PK Park at noon.
GAME NOTES -
Designated hitter Kyle Garlick pushed his team-best hit streak to 15 games on Saturday with a single in the second inning. He scored on Kruger's double.
Baumgartner's first inning single pushed his hit streak to six games.
Krook now has 43 strikeouts on the season, still a conference high. Attendance at PK Park was 2,067.