CORVALLIS — One swing turned a potential lost weekend into a winning one for Jordan Lennerton and the rest of the Oregon State baseball team.

The junior first baseman was 1-for-9 for the weekend when he came up against USC closer Paul Koss with one out in the 11th inning of Saturday’s series finale at Goss Stadium. He’d stranded five runners and hit into a rally-killing double play in the eighth inning of a 4-1 defeat on Friday night, and was overmatched in two previous at-bats on Saturday.

But Lennerton had a plan against Koss, one of the Pacific-10 Conference’s premier relievers. He hoped to loft a ball the opposite way and let the stiff wind blowing out to left field finish the job.

It worked to perfection. The left-handed hitter got a pitch he could handle and whistled it over the wall at the 350-foot mark for a 9-8 comeback victory that won the series and kept OSU in contention for a third consecutive Pac-10 championship.

“I was looking for fastball away ... get it up in the jetstream,” said Lennerton, whose other 2007 homer, a 3-run shot against Evansville in the March 8 home opener, landed in almost the identical spot. “They’d been throwing me a lot of fastballs and I hadn’t been putting a good swing on any of them.”

He added: “I thought it had a chance; I knew I had a double for sure. I thought it might go off the wall, but it got enough wind and got out of here. The wind was definitely a factor.

“I needed to do something big today for the team. I’ve been struggling, and had a lot of opportunities, but couldn’t capitalize with the chances yesterday.”

The crowd of 1,547 saw plenty of late-inning heroics that enabled the Beavers (25-7, 2-4) to overcome a sixth-inning meltdown when USC (19-14, 2-4) scored six times with two outs to zoom ahead 7-5.

Mike Lissman’s two-run, two-out homer off the left-field foul pole tied it 8-8 in the eighth. And junior closer Eddie Kunz, who hadn’t pitched more than 32/3 innings in a game since his senior year at Parkrose High, went 51/3, escaped several jams, struck out five and and held USC to one run on two hits.

“I was really focused and really wanted to get that win. I wasn’t going to let anyone take it from me,” Kunz said. “I was working my butt off trying to do my best and show everybody I can throw extended innings.

“I was going to (pitch) until they took me out; they probably would have had to drag me off that mound. But I was perfectly fine when Lennerton ended it.”

Through five the rally looked unnecessary. Three early RBIs by catcher Mitch Canham staked OSU starter Daniel Turpen to a 5-0 lead and he led 5-1 with two outs and no one on in the sixth when he crumbled. After throwing one pitch several feet behind one batter, a hit batsman, an infield single and a walk loaded the bases. He then plunked Lucas Duda on a 2-2 pitch to force in a run, and was replaced by Anton Maxwell.

Maxwell’s first pitch hit Roberto Lopez to drive in another run. Hector Estrella crushed his third offering well over the left-field fence for a grand slam and a 7-5 Trojan lead.

OSU trailed 8-6 when Darwin Barney doubled off reliever Hector Rabago with two gone in the eighth. Lissman then pounded a 1-0 curveball to left and the only question was whether it would stay fair. It did — aided by some Fiskian-like contortions from Lissman — and bounced off the screen about halfway up the foul pole for an 8-8 tie.

“As soon as I hit it, I kind of leaned back a little bit, leaned with it, and the wind was good for it,” Lissman said. “I was sitting a little bit,” waiting for the curve, “but it’s see ball, hit ball, run. You don’t even know what you hit sometimes.

“That was a great character builder. It’s time to build a little momentum going into Cal, and I think we did a great job of doing that.”

The Beavers host Portland at 4 p.m. on Tuesday and then are home with California on April 13-15 and UNLV on April 20-22.

Oregon State 9, USC 8

USC 000 016 010 00 — 8 8 1

OREGON STATE 030 201 020 01 — 9 14 2

Vasquez, Rabago (5), Couture (8), Koss (10) and Stock; Turpen, Maxwell (6), Kunz (6) and Canham. WP: Kunz (2-0). LP: Koss (2-2). 2B: Owen (USC), Duda (USC), Buss (USC), George 2 (OSU), Barney (OSU), Lechelt (OSU). HR: Estrella (USC), Lissman (OSU), Lennerton (OSU).

HIts: USC 8 (Owen 2, Estrella 2, Green, Duda, Buss, Perren), OSU 14 (Lissman 3, Canham 2, Lechelt 2, George 2, Hopkins, Barney, Lennerton, Wells, Solomon).

RBIs: USC 8 (Estrella 5, Lopez 2, Buss), OSU 7 (Canham 3, Lissman 2, Lennerton, George).