CORVALLIS – It says a lot about Oregon State's pitching that – against USC, a team that came into this series with seven .300 hitters – the question going into Sunday's series finale was whether the Beavers would get another shutout.

After all, OSU had done just that a day earlier, and starter Ben Wetzler had thrown a shutout in his previous start.

Another shutout, and the Beavers' team ERA would have dipped below 2.00. It would have been their ninth shutout of the season, the highest total for OSU since 1967.

Well, USC second baseman James Roberts ruined those story lines with a solo home run in the fourth inning, but Wetzler was in command throughout the seventh-ranked Beavers' 6-1 win, his fourth victory in his last four starts.

We still have this story line, though:

It was the first time ever that Oregon State (34-8, 14-4 Pac-12) has swept USC – a program with 12 national titles to its credit – in a three-game series.

"It's nice, but I mean, the girls just swept Arizona,'' OSU coach Pat Casey said, referring to the Beavers' first-ever softball sweep of the Wildcats, which finished about an hour earlier a few hundred yards away. "I mean, come on, we got nothing on them.

"Yeah, I guess that's cool for the program – nothing that we're really hanging our hats on.''

Casey said his offense "made strides,'' but then again, the Trojans (16-26, 8-13) have the worst ERA in the Pac-12, now at 4.95 – nearly three runs higher than Oregon State's (2.02).

It was Oregon State's pitching staff that assumed a starring role this weekend. In 27 innings, the Beavers gave up two walks and four runs – three of them meaningless, ninth-inning runs Friday in a game that already was decided.

"Pitching was outstanding all weekend,'' Casey said, "especially against a team that I think swings the bat pretty good.''

With pitching like that, all a team needs is the little things on offense, and they got plenty of those from second baseman Andy Peterson on Sunday.

Peterson's sacrifice bunt in the first helped the Beavers take an early lead, and his sacrifice fly in the second made it 3-0. In the fifth, he walked, stole second and scored on Dylan Davis' league-leading 16th double of the season. And in the seventh, he beat out an infield single, took third on a hit by Michael Conforto, and scored on Davis' sac fly. To top things off, Peterson legged out another infield hit in the eighth.

That was plenty for Wetzler, who comfortably threw 101 pitches, 72 for strikes, before coming out after eight innings.

"That's probably the most efficient I've ever been in my life,'' said Wetzler after the game, which drew a crowd of 2,547 to Goss Stadium on a mostly sunny, 68-degree day.

Casey thought about letting Wetzler finish things off and get a second straight complete game, especially when Wetzler lobbied to do so, but Casey sent closer Scott Schultz in for what proved to be an uneventful ninth.

In Friday's series opener, Casey let starter Matt Boyd have his way, sending him out in the ninth and watching the Trojans score three times.

"Being the soft guy that I am, I let (Boyd) talk me into it,'' Casey said. "I stood my ground on the junior (Wetzler) today. Only seniors get to tell me what to do.''

The Beavers, with no midweek games, are at home again next weekend when California comes to Corvallis. Oregon State will enter the weekend percentage points ahead of Oregon, which swept Stanford with another late rally Sunday.