OKLAHOMA CITY — The NFL’s confusing catch rule doesn’t apply here.

That was good news for the Huskies and bad news for the pro-Sooners crowd of 8,561 during the first session of the Women’s College World Series on Thursday at ASA Hall of Fame Stadium.

Washington, the fifth seed, escaped with a 2-0 victory over No. 4 Oklahoma in the opening round, thanks in part to a controversial catch by Trysten Melhart.

The Huskies (50-8) survived an intense rally attempt by the two-time defending national champions and advance to play No. 1 Oregon in the winner’s bracket Friday at (4 p.m., ESPN).

The Ducks (53-8), who opened double-elimination bracket play with an 11-6 win over Arizona State, swept Washington in Seattle en route to the program’s fifth Pac-12 title in the last six years.

“You can’t look back, you can’t get too stuck in the past,” Washington pitcher Taran Alvelo said. “I think that’s what makes us as successful as we are is because we are able to look past the hardships and the obstacles that come our way and it pulls us together as a team.

“What happened (against Oregon) is ultimately, I think, why we have as much fight as we do now.”

The Sooners (55-4) had won 16 consecutive games dating back to a 5-0 loss to Oregon on April 19 at Jane Sanders Stadium.

Sis Bates brought home a run on a fielder’s choice, and Julia DePonte added an RBI single in the fifth after Paige Lowary temporarily replaced ace Parker Paige in the circle.

That would prove to be all the run support needed for Washington starter Gabbie Plain (21-4) and Alvelo.

The Huskies loaded the bases with no outs in the top of the sixth, but Parker wiggled out of the jam unscathed. The Sooners took the momentum into the bottom-half of the frame as Sydney Romero and Jocelyn Alo reached on back-to-back singles off Plain with two outs.

Alvelo was brought in, and Shay Knighten hit her first offering in Melhart’s direction. The right-fielder made a diving snag, bobbled the ball, regained possession and then dropped the ball while hopping up off the grass.

“I would say that ranked in the top 10 of great catches I’ve ever made,” Melhart said. “In the moment, I felt like I had it. I went for it, I did catch it.”

Second base umpire Scott Mair immediately ruled Knighten out, otherwise the base runners would almost certainly have scored to tie the score.

“The right fielder caught the ball. She made the catch. And the ball was dropped on the transfer, trying to take the ball from her glove to her hand,” Vickie Van Kleeck, the NCAA secretary rules-editor explained to a pool reporter after the game. “This is considered a secondary motion, so it’s ruled a catch.”

With two outs in the seventh, shortstop Bates made two diving stops but was unable to throw out either Nicole Mendes or Caleigh Clifton. Alvelo calmly struck out pinch-hitter Kylie Lundberg to end the game.

"We haven't beaten them yet this year," Washington coach Heather Tarr said of the Ducks, who last loss to the Huskies when in the opening round of the 2017 WCWS. "We have to play our game."

Parker (29-3), who had an 8-0 record at the WCWS, took the loss. Her previous loss this season came against the Ducks opposite Megan Kleist’s one-hit shutout performance.

“Losing is never fun, but I know how much fight our team has and how much heart that we have,” said Parker, who will likely start again in an elimination game against Arizona State on Saturday. “I fully believe that this team can do anything.”

Also Thursday

UCLA 7, Florida State 4: Kylee Perez hit a three-run homer in the sixth inning to help UCLA rally past Florida State. UCLA's Rachel Garcia, the USA Softball Collegiate Player of the Year, pitched a complete game to earn the win. She gave up four hits and struck out 15. Garcia held Florida State hitless through four innings before the Seminoles broke through in the fifth. Cali Harrod walked, stole second, moved to third on a throwing error and scored on a single by Dani Morgan. Later in the inning, Sydney Sherrill sent a hard shot in the air toward the left-field line with the bases loaded. UCLA left fielder Kinsley Washington misplayed the ball, and three Seminoles scored on the double to make it 4-0. Perez's homer highlighted a six-run inning that gave the Bruins the lead for good.

Florida 11, Georgia 3, 5 inn.: Aleshia Ocasio hit a three-run homer and pitched a complete game to help Florida win the battle of SEC teams. Ocasio gave up three runs and seven hits and allowed Florida coach Tim Walton to save ace pitcher Kelly Barnhill. Hannah Adams had two hits, including a solo homer and Jordan Roberts had a two-run blast for the second-seeded Gators (56-9). Alyssa DiCarlo and Justice Milz hit home runs for Georgia (48-12). DeCarlo's, whose homer was her 21st of the season, had three hits.  Georgia led 2-0 before Florida responded with five runs in the bottom of the first, highlighted by Ocasio's blast. Florida scored another in the second, two in the fourth, then three in the fifth to end the game. Georgia used four pitchers and didn't get more than 2 1/3 innings from any of them.