CORVALLIS — Garret Forrester was raking, Mason Guerra was bombing and Oregon State’s relief crew found the mark as the Beavers prevailed in a slugfest with Oregon Tuesday night at Goss Stadium.

Forrester continued his torrid hitting with three hits and three RBIs, Guerra ripped a pair of tape-measure home runs and Tyler Mejia, Aiden Jimenez and Ben Ferrer combined to limit the Ducks to four hits, no walks and no runs over the final six innings of an 11-6 non-conference victory.

The 15th-ranked Beavers (31-13 overall, 14-10 in Pac-12 play) beat the 17th-ranked Ducks (30-14, 13-8) for the third time in four games in this year’s Civil War series. Oregon State also moved up in the D-I RPI rankings to No. 25, while Oregon fell to No. 20 in the rating system that is used to help determine seeding in the NCAA Tournament.

The game started as if it were a batting practice exercise. Oregon led 5-4 when the Beavers sent 10 batters to the plate in the bottom of the third inning, using four consecutive doubles to plate five runs and take a 9-5 advantage.

Guerra provided OSU’s other two runs with solo shots to left-center field in the fourth and sixth innings.

The 6-3, 205-pound sophomore from Westview High ripped a changeup 430 feet in the fourth and followed that with a 441-foot blast off a fastball in nearly the same spot in the sixth. Guerra said he was irritated at himself for being too passive in his first two at-bats, a ground-out and a strikeout.

“On my first home run, I decided to be real aggressive,” he said. “I decided to loosen up and try to get my swing off. I used the same approach for the second one.”

Guerra, who drove in four runs and had a two-run homer Saturday against Arizona, is now hitting .306 with an on-base percentage of .410. The right-handed hitter, who has batted cleanup for the Beavers the last 14 games, has eight homers and 36 RBIs in 41 games this season.

“Mason has progressively gotten better throughout the season,” OSU coach Mitch Canham said. “He  has morphed his way into that money spot in the order and is driving the ball. He is growing up really fast right before our eyes. He has big ability to drive the ball out of the ballpark, and is showing patience at the plate, too. Drawing walks shows me he is doing it the right way.”

Guerra credits assistant coach Darwin Barney with guiding him through video review of his swing.

“Going over every at-bat with Darwin helps a lot — getting an understanding of how (opponents) are pitching me, what I’m going to see in each at-bat,” Guerra said. “And the guys around me. … there is a lot of confidence in this group. We trust each other. It makes it fun to go out and compete.”

Guerra, who didn’t make his first start until the fifth game of the season, was the designated hitter Tuesday night. He has also started games at third base and in left field.

“When I DH, it’s a day to get off my legs a little bit,” he said. “I’m still being locked in in all my at-bats. Whether it’s left or third or first, wherever I am thrown out there, I am ready to compete.”

Forrester, coming off a career 5-for-6 performance with five RBIs in Sunday’s 11-10 win over Arizona, followed it with another come-through performance at the plate Tuesday. The Beavers had a dozen hits, five walks and two hit-by-pitch, and bombarded Oregon starter Jackson Pace for eight hits and six earned runs in 2 2/3 innings.

Oregon, meanwhile, also totaled 12 hits in the game. The Ducks got to Oregon State’s first two pitchers — Justin Thorstenson and David Grewe — for eight hits and six earned runs in the first three innings in what amounted to a bullpen game for the Beavers. Freshmen Mejia and Jimenez followed with quality work over the next five innings, and veteran Ben Ferrer threw a flawless ninth.

“Never a bad deal to have Benny enter in the ninth with a five-run lead,” Canham said. The relief corps “did a great job. Mejia came out very competitive, mixing pitches. Mejia going multiple innings, Jimenez going multiple innings as well. … they were rolling and filling up the zone with strikes.”

Oregon State has won eight of the last nine Civil War meetings, including a five-game sweep last season. Canham went the Chip Kelly route Tuesday night, saying that the interstate rivalry means no more to him than any other Pac-12 game.

“I was proud of our guys for getting after them, but I don’t think we do or should look at any opponent in a different light, especially in the Pac,” he said. “Everyone is really good. I don’t put any emphasis based on what that team is, in-state rivalry or out of state. You have to approach the game the same every time out.”

Canham played at Oregon State from 2004-07, when Oregon had yet to reinstate its program. He said beating the Ducks doesn’t particularly help in recruiting — “you’re recruiting against everybody” — and said he learned something from his predecessor, Pat Casey.

“Case said, ‘You really don’t like any opponent,’ ” Canham said. “Everyone knows when it’s time to compete, there are no friends.”

Things weren’t very friendly at the end of Sunday’s game, when a fired-up Ferrer had something to say toward the Oregon dugout after striking out Drew Smith on three pitches. Oregon coach Mark Wasikowski had a few words with Canham afterward, no doubt discussing the subject.

It may be just another game to Canham, but it wasn’t that way for Casey, who liked nothing better than to beat the Ducks. Not that way, either, to the fans of both schools. Alums who are helping fund a $6.1 million hitting facility project like the fact that the Beavers have won 44 of 68 meetings with Oregon since the Ducks reinstated baseball in 2008.

It’s special for the players, too.

“It’s a little extra,” Guerra said. “It means a little more when you play the Ducks. To beat them three out of four times this season feels real good.”

I would like to have asked Wasikowski about that and several other things afterward, but by the time I arrived where Oregon’s assistant coaches were meeting with the players, UO sports information representative Todd Miles said the head coach had departed.

The Ducks are still very much alive in the race for not only the opportunity to host one of 16 regionals in the NCAA Tournament, but also to claim the Pac-12 regular-season championship and No. 1 seed in the Pac-12 postseason tournament May 23-27 at Scottsdale, Ariz. Nine teams advance to the latter event, which will feature three pools of three teams in a pool and round-robin competition. The teams that reach the championship game will get four extra games.

Stanford leads the Pac-12 with a 15-6 conference record, followed by Arizona State at 14-6, Oregon at 13-8 and Oregon State at 14-10. Oregon has three three-game conference series left, beginning Friday at Southern Cal. The Ducks also play series at home against Washington and on the road at Utah.

Oregon State, meanwhile, has conference series remaining against Utah at home, beginning Friday, and at UCLA. The Beavers, 19-5 since being swept at Stanford in mid-March. also have a pair of non-conference games left against Portland and a regular-season finale three-game series against non-conference foe Western Carolina at Goss.

“We are trending in the right direction,” Canham said. “Our offense is clicking. The pitchers are going well. We have built some base-running identity.

“Still, I never try to think too far ahead. As soon as that game ended, it’s prepping to take on Utah. We talk about not get too high, not get too low. … We have told each other, if we do our job, we will be where we need to be. I don’t want our guys thinking about (the future). I want them focused on today.”

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