CORVALLIS, Ore. -- Neither Mother Nature nor Oregon's hurlers proved any match for Oregon State's bats Monday, as OSU won the final two games of its season-opening Pac-12 series against rival Oregon 5-4 and 7-1.

The wins in two of three games clinched a Beaver victory in the softball version of the Civil War Series and tied the year-long athletic battle between the two schools at 6-6.

"I'm extremely happy with the way our girls competed," Oregon State head coach Kirk Walker said. "We've had a good start to the year, but as we all know, the Pac-12 schedule presents an entirely different set of challenges each and every day. This weekend we met those challenges, executed our game plan and took advantage of our opportunities. We will have to continue to do those things as we get deeper into our conference schedule if we want to be successful."

Game 2 of the three-game set was suspended on Sunday in the top of the second inning because of a steady downpour, and was resumed and completed Monday. OSU (23-8, 2-1 Pac-12) jumped out to an early lead in the first inning of that contest, scoring four runs on three hits and one error.

Dani Gilmore led off the game with a single to right field and advanced to second on a bunt single by Hannah Bouska. Shortstop Elizabeth Santana followed those hits with a single of her own to drive in Gilmore, and both Bouska and Santana moved up a base on the unsuccessful attempt to gun down Gilmore at the plate.

Bouska scored on a wild pitch to make it 2-0 and an error by Oregon's third baseman plated another run for OSU. A walk and a hit by pitch loaded the bases for Lea Cavestany, who did her job putting the ball in play to the middle of the field, driving in the Beavers' fourth run of the opening frame on a fielder's choice grounder to make the line 4-0 in Oregon State's favor.

No. 15 Oregon (19-6, 1-2 Pac-12) would battle back into the contest, scoring once in the fourth and three more times in the sixth to force extra innings. In the eighth, Ally Kutz led off with a single to right-center field and was run for by sophomore Isabelle Batayola. Cavestany took Kutz's lead and singled after the Beaver catcher and Ya Garcia moved both Batayola and Cavestany into scoring position with a sacrifice bunt.

The Ducks walked Gilmore intentionally to load the bases and brought in ace Jessica Moore to pitch. Moore was able to get the second out of the inning, but hit Santana with an errant toss to force in Batayola from third and give the Beavers the win.

Santana was 3 for 3 with two RBI and Paige Hall tossed 2.1 innings of one-hit relief to earn the win.

In the rubber match, Oregon State made sure there were no such dramatics, pounding out seven runs on eight hits in the fourth and fifth innings to run away with a 7-1 victory.

In the bottom of the fourth, Paige Hall, who had just come into the game to pitch in the top of the inning, led off the frame with a line-drive home run to left field, her team-leading sixth of the year, to essentially open the floodgates. Guzy followed with a double and the Beavers tacked on another thanks to an RBI single by Cavestany.

In the fifth, Bouska led off being hit by a pitch and Santana singled to left field to put two on for Desiree Beltran. Oregon State's third baseman took the second pitch she saw from Moore and deposited it onto the hill in left for a three-run homer, her fifth of the season.

Guzy doubled again following an OSU home run, came around to score on a double by Cavestany and Mary Claire Brenner capped off the onslaught with a pinch-hit RBI single to drive in Cavestany.

Hall again came on in relief, giving up only two hits in four innings to push her record on the year to 10-1 while lowering her ERA to 1.96.

Beltran, Guzy and Cavestany went a combined 5 for 9 with five RBI in the nightcap. The Beavers put up five earned runs on Oregon's Moore, who came into the game with a 13-4 record and 1.34 ERA.

The wins gives Oregon State its first back-to-back wins against the Ducks since 2008 and sealed only the Beavers' third Pac-12 series victory since 2008. The six-run margin of victory in the finale was OSU's largest in a Pac-12 game in almost four years, going back to an 8-0 win in six innings against then-No. 22 California on April 12, 2008, and the seven total runs were the most for the program in a conference game since they scored 10 against Stanford on April 11, 2010.

The 7-1 final was also the Beavers' largest victory against Oregon in more than a decade, since an 11-2 win on April 14, 2001. Oregon State won two of its first three conference games for the first time since 2007, which is also the last year the Beavers advanced to the postseason.