Left fielder Brittany Williams got the party started, hitting a two-run double inside the right field line on her birthday for an early 2-0 lead in the bottom of the third.
The Sooners added two more in the frame, first when third baseman Shelby Pendley raced home on a steal and an error, then on center fielder Destinee Martinez's single up the middle that plated pinch runner Erica Sampson.
In the meantime, Ricketts took care of batter after batter, striking out half of the 28 she faced.
She allowed just five hits in her seventh complete game shutout of the season, extending her scoreless streak to 30 1/3 innings.
OU made it 5-0 on a fielder's choice in the fifth, and Ricketts helped her own cause with a solo shot in the sixth that capped off the scoring.
The Sooners get back to action Saturday with a doubleheader against Nebraska starting at 1:30 p.m. CT at Marita Hynes Field, with the second game slated for 30 minutes after conclusion of the first.