The fourth-seeded Sooners (53-8) struck for four runs in the third inning against Dallas Escobedo (24-8) to take control. Ricketts had an RBI single to tie it at 2 and Jessica Shults followed with a two-run double that nicked off of right-fielder Alix Johnson's glove as she dived to catch it.
Shults then came in to score when third baseman Haley Steele lost Norris' potential inning-ending popup and let it fall.
The Sooners will face either top-seeded California or No. 2 seed Alabama in the best-of-three championship series starting Monday night. It's the first time Oklahoma has made it to the finals since winning its only national championship in 2000, when the title was decided with a single game.
"I just love the tenacity of this team, and to find a way to play for a national championship has been our ultimate dream and our ultimate goal. And to know that it has a chance for reality, it is unbelievable," coach Patty Gasso said.
"The hard work and effort they put in, there's not another team that deserves it more than my Sooners."
Ricketts (36-7) gave up Annie Lockwood's two-run double in the first but was able to limit Arizona State (53-11) to three runs despite giving up eight hits and a season-high four walks.
"All I remember is every inning was a battle. One through nine, those hitters were just giving me a battle," Ricketts said. "They were making me work."
Ricketts struck out Katelyn Boyd and Johnson, both hitting over .400 at the start of the day, when they represented the tying run in the sixth. She then struck out Amber Freeman, Lockwood and Sam Parlich to end the game after Steele had led off the seventh with a single.
"We had just that one bad inning where a few squeak in and they just fall and we don't get those plays when we needed them," Lockwood said. "But we made her work very hard today. ... We had a lot of 3-2 counts. We made her work really hard. We were in her head, I feel like, the whole game."
The Pac-12 has won the last six NCAA titles, but Cal will need to beat the Crimson Tide twice to keep alive a chance for a seventh in a row. Oklahoma beat the Golden Bears on Friday night in the double-elimination tournament.
"The way we've gone through this tournament, we've played the best and I like it that way because we've earned the right to be here," Gasso said.
Ricketts hadn't given up an earned run in 40 consecutive innings before yielding two in the first.
Norris cut Oklahoma's deficit in half with her lined shot over the center-field fence in the second, and Ricketts was back ahead after Johnson fully extended to try to catch Shults' liner to the gap in right-center but had the ball pop out of her glove.
"It's a different ballgame if a couple of ours fall in," Sun Devils coach Clint Myers said. "It's just what it is. We make no excuses. That's just the way it happened, and great teams have to be ready for the adversity of that.
"We've got to be able to bounce back and go, and we came up just a little bit short today."
More Sports Headlines
So long to the Silvertips beat, but not goodbye Drew Jackson's monster season with AquaSox resonating with M's brass Bullpen bounces back, Mariners beat White Sox 8-6 Andrade wins Boeing Classic for 2nd Champions Tour title Uhl leads AquaSox to 7-2 victory over Volcanoes IndyCar's Wilson in coma, in critical condition after Pocono accident USC's Sarkisian apologizes for behavior at team event Federer, Serena Williams win Western & Southern Open titles
Our new comment system is not supported in IE 7. Please upgrade your browser here.