OMAHA, Neb. – In what we thought was going to be a close, tight game, top-seeded Oregon State turned it into a rout.

Bryce Fehmel allowed two hits and a run in eight innings, and KJ Harrison hit the first College World Series grand slam at TD Ameritrade Park, as the Beavers beat fourth-seeded LSU 13-1 Monday evening to give them their second 23-game win streak of the season.

The Tigers (49-18) will face Florida State in an elimination game on Wednesday evening at 6 p.m. The winner of that game will have to beat OSU (56-4) on both Friday and Saturday to win the bracket and advance to the CWS Championship Series.

Fehmel (6-2) kept LSU scoreless for six innings before Zach Watson (2 for 4) whacked a solo homer with one away in the seventh to avoid the shutout.

“It all started with Bryce,” said Pat Casey, OSU head coach, “just coming out and being so good. And we knew we were playing a really good club. We probably caught them on a day where they didn’t play as well as they normally do. And we played very, very well.”

Fehmel (pictured) walked three and struck out three.

“I guess the main thing was keep them off balance as best I could,” Fehmel said. “Mix all three pitches for strikes. And I did that for eight innings to the best of my ability, and it worked out.”

The Beavers had 11 hits and drew 12 walks for constant base-runners in the contest.

OSU struck quickly in the top of the first. Steven Kwan (2 for 4, 3 R) bunted the first pitch to the first baseman and beat the throw for a base hit. He was moving on the next pitch as Nick Madrigal (3 for 6) grounded out to short. Trevor Larnach (2 for 3) singled up the middle to drive in Kwan with the first run.

“The two guys at the top of the order do a great job of getting on,: Larnach said, “and mine and KJ’s job and everybody else’s job to get them in. I was fortunate to get a pitch to do it on and help the team out.”

“We wanted to be aggressive,” Casey said. “I wanted to take the first shot. And Kwan did a great job, made a great bunt. And I thought: What the heck, let’s just go again. So we took off. Nick actually got a good pitch to get a hit-and-run on. And Trev got the big hit and got us ahead 1-0.”

LSU starter Eric Walker (8-2) retired OSU in order in the second and had a 2-2 count on the leadoff hitter in the third when he was forced to leave the game.

“His forearms tightened up again,” said Paul Mainieri, LSU head coach, “which is what happened a week ago after an intrasquad game. He had gone through a bunch of rehab and threw a couple of side sessions and felt great, felt 100 percent. His warm-ups today in the bullpen were great. His first two innings were great. And then on the third pitch of his warm-ups for the third inning, he just felt it tighten up again. And so obviously we had to take him out. We don’t think it’s anything serious. I think it’s just a fatigued muscle. He’s pitched more innings this year than he ever has, and I think he’s running a little bit dry.”

The Tigers, who had their 17-game win streak snapped, would tie a CWS record by using eight different pitchers.

The Beavers would put up crooked numbers from the fifth through eighth innings. Larnach had a two-run single in the fifth to give OSU a 3-0 lead. Madrigal drove in a run on a groundout in the sixth before Harrison went deep for the ninth time, the first CWS grand slam since 2010, as the lead ballooned to 8-0.

“I was just looking for a good pitch to hit,” Harrison said, “and put a good swing on it, keep it simple and stay relaxed, and I was able to do so. That’s the kind of stuff you dream of growing up as a little kid, and for it to come true and at such a big stage, it was an amazing feeling. But the main thing for me is what it did to help the team out and put some more momentum on the board. And we attribute that to our success as a team this whole season so far. We’re out there for one another. We pick each other up, and it’s a lot of fun being a part of.”

Cadyn Grenier had a sacrifice fly in the seventh prior to Madrigal’s two-run double, making it 11-0. Grenier had a two-run single in the eighth to make the final 13-1.

Harrison drove in four, while Larnach, Madrigal and Grenier each knocked in three.