EUGENE, Ore. - The top-ranked Ducks scored nine runs in a big second inning before Stevie Jo Knapp's three-run homer in the sixth finished off No. 3 ranked Arizona State, 12-2, in six innings on Saturday afternoon at Howe Field.

Oregon has now run-ruled three top-5 opponents this year, also winning via the mercy run against then-No. 5 ranked Washington, 8-0, and then-No. 1 ranked UCLA, 12-4.

The Ducks (47-6, 18-2 Pac-12) posted 12 runs on 11 hits with no errors while the Sun Devils (43-8, 14-5) tallied two runs on just three hits with no errors.

Oregon's 12 runs were the second most ever scored the Ducks against the Sun Devils in 89 all-time meetings as the Sun Devils were run-ruled for the first time by any foe since 2010.

Karissa Hovinga (15-1) picked up the win for the Ducks after allowing only two unearned runs on three hits and a walk in six innings. She struck out five batters and threw just 69 pitches.

“Karissa pitched probably the best game I’ve seen her throw and it came against an excellent hitting club," head coach Mike White said. "That was really the catalyst for us right there.”

Hovinga has pitched well against top-tier competition this season. The junior with Canadian national team experience allowed just one run on six hits in five innings against then-No. 1 ranked Florida and also allowed just one run in starts against Stanford and then-No. 5 ranked Washington in league play.

Oregon's offense made sure Hovinga didn't need to be quite that sharp against the Sun Devils.

After a scoreless first inning, the Ducks erupted for nine runs on eight hits in the second inning. The Ducks have had innings of nine runs (ASU), 11 runs (Oregon State) and 15 runs (California) against Pac-12 teams this year.

 After a ground ball out, Janelle Lindvall started the big second inning with a single up the middle. She was actually out earlier in the at-bat, but an illegal pitch was called and wiped out the third strike. Lindvall took advantage with a single which sparked the Ducks.

Alexa Peterson, Kailee Cuico and Karine Shaver all followed with singles, putting the Ducks ahead 2-0. Nikki Udria drew a walk to load the bases for Courtney Ceo, who delivered with a single to right which scored a pair. Alyssa Gillespie drove in two more with a triple to right center and she scored an at-bat later when Janie Takeda doubled down the first base line.

After Takeda's double, Arizona State made a pitching change, bringing on ace Dallas Escobedo to relieve starter Mackenzie Popescue. After Escobedo got a strikeout for the second out of the inning, Lindvall came back up to bat after leading off with a single. The sophomore catcher slugged a 2-2 pitch to left center as the Ducks hit for the cycle in the inning.

Arizona State got a pair of runs back in the third when the Sun Devils took advantage of an extra out, coming on a dropped third strike to start the inning.

Neither team scored in the fourth or fifth but the Ducks walked off with the run-rule win in the sixth when Knapp crushed a three-run homer to left center.

“At practice, nobody hits the ball further than she does," White said. "She can really launch it. We keep trying to give her opportunities when we think the time is right, and today she came through. I’m just happy for her because she works really hard.”

Knapp's three RBIs were a game-high while Lindvall and Peterson each had two hits to pace the Ducks.

The rubber match of the three-game series with the Sun Devils starts at 2 p.m. on Sunday at Howe Field. Pac-12 Networks will televise the game live.