OKLAHOMA CITY — Kinzie Hansen homered and knocked in three runs, and three-time defending national champion Oklahoma opened its title defense with a 9-1 win over Duke in six innings on Thursday in the Women’s College World Series.

Hansen, Jayda Coleman and Alyssa Brito each had two hits for the second-seeded Sooners (55-6).

Kierston Deal threw 2 1/3 innings of scoreless relief to get the win for Oklahoma, which looks to become the first team to win four straight national titles.

Cassidy Curd, who got both wins against Missouri in super regionals, started and gave up one run on three hits in two innings. Jala Wright a second-team National Fastpitch Coaches Association All-American, allowed five runs on four hits in one inning and took the loss.

Oklahoma will play No. 6 seed UCLA on Saturday, with the winner reaching the semifinals. Duke will play No. 14 Alabama in an elimination game on Friday.

The 10th-seeded Blue Devils (52-8) made their first World Series appearance under coach Marissa Young. Duke led Thursday’s game 1-0 when Hansen’s two-run blast in the third put the Sooners ahead. Alynah Torres added a two-run shot later in the inning to make it 4-1.

Duke loaded the bases against Oklahoma starter Kelly Maxwell with two outs in the fourth, and Oklahoma coach Patty Gasso replaced her with Deal. Jayda Coleman’s diving catch in centerfield saved the Sooners from allowing any runs.

Cydney Sanders’ two-run blast in the fourth made it 6-1. Brito closed the scoring with a single that knocked in two runs in the sixth.