OKLAHOMA CITY >> Tiare Jennings and Jana Johns hit grand slams and No. 1 seed Oklahoma rolled past No. 9 seed Northwestern 13-2 in five innings today on the opening day of the Women’s College World Series.

The defending national champion Sooners pounded out 11 hits. Northwestern’s Danielle Williams (31-5) — a first-team NFCA All-American pitcher — lasted just three innings and took the loss.

Oklahoma (55-2) advanced to play rival Texas on Saturday in their first ever World Series meeting. Texas is responsible for one of Oklahoma’s losses this season, though the Sooners won two of the three meetings. Saturday’s winner would be just one victory from a spot in the best-of-three championship series.

Oklahoma coach Patty Gasso considers it a plus that the Sooners are familiar with the Longhorns.

“I think it’s a benefit,” Gasso said. “We know what we’re dealing with. We know what to work on. We’ve seen it three times.”

Northwestern (45-12) will play UCLA in an elimination game Friday.

Northwestern’s Rachel Lewis’ solo blast over the left field fence in the third inning opened the scoring. It was her 23rd homer of the season.

That was the only hit Oklahoma starter Hope Trautwein (19-1) allowed. She struck out seven and walked five in 4 2/3 innings to claim the win.

“This is the biggest stage that anyone will ever play on, so I really stuck to my process,” Trautwein said. “Deep breaths. Slowing my heart rate down. Really focus on the game. Lynnsie Elam had told me some advice before I came in — look at the crowd once, and don’t look at them again. That’s what I did.”

Oklahoma took over in the bottom of the third. The Sooners tied it up on an RBI single by Johns that scored Rylie Boone. Williams walked Jocelyn Alo — the two-time USA Sotball Collegiate Player of the Year who graduated from Campbell High School — to bring up Jennings with the bases loaded. Jennings, also a first- team All-American, put Williams’ first pitch over the fence in center field to give the Sooners a 5-1 lead and control for good. It was Jennings’ 25th home run of the season.

“I kind of just stuck to my timing like I did, and I kind of had a feeling that it was going to come first pitch, so I saw the ball up in the zone and just went from there.” Jennings said.

Alo didn’t get the big hit in the inning, but she talked to the team beforehand and got her point across. She finished the day with a hit, scored a run and was walked twice.

“Jocelyn Alo jumped in,” Gasso said. “And that gets very stern and gets to a place where I need to walk away because … we have a pretty strait-laced program, but when Joce jumps in, she’ll say it the way she means it. I just step out so she can be herself. The response was through the roof.”

Johns’ grand slam in the fourth put the Sooners up 13-1.

Jordy Bahl got the last out in relief for Oklahoma. The NFCA Freshman of the Year hadn’t pitched in about a month because of an arm injury. She gave up two hits but got a feel for what it’s like to be in the circle in Oklahoma City.

“It was a victory just seeing her being able to pitch because truly I didn’t think she would be able to come back,” Gasso said. “She’s done everything right, and she’s done it 24 hours a day every day since it happened. To see this going on is a victory.”

In other games today, Texas beat UCLA 7-2, Florida beat Oregon State 7-1 and Oklahoma State beat Arizona 4-2.