OKLAHOMA CITY (AP) — Tiare Jennings and Jana Johns hit grand slams and No. 1 seed Oklahoma rolled past No. 9 seed Northwestern 13-2 in five innings on Thursday 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.

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.

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 — 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.

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