OKLAHOMA CITY (AP) -- Lauren Chamberlain rounded first base waiting, wondering and praying even that her long drive would be a home run and not just a foul ball.
When third-base umpire Christie Cornwell raised her right hand and signaled that it was a home run, she thrust both arms into the air and ran around the bases into a celebration at home plate.
Chamberlain's two-run home run in the bottom of the 12th inning lifted top-seeded Oklahoma to a 5-3 win against Tennessee on Monday night in Game 1 of the Women's College World Series finals. It was her 30th of the season, tying for the most in the nation this season.
"I really couldn't believe it," Chamberlain said. "It was awesome."
The Sooners capitalized on a dropped pop-up to rally from three runs down in the 11th after Tennessee' Madison Shipman broke a scoreless tie with a three-run home run off of national player of the year Keilani Ricketts (35-1).
Ellen Renfroe (19-5) was able to match Ricketts until the end, striking out 13 for seventh-seeded Tennessee (52-11). She threw 180 pressure-packed pitches, eight less than Ricketts.
It ended up as the longest game in the championship round since 1984, when UCLA beat Texas A&M 1-0 in 13 innings back when a single game decided the NCAA softball title.
"There's no break in the Oklahoma lineup. Every single pitch, it's all you've got because if you don't give everything then it's going to get hit out. Something bad's going to happen," Renfroe said. "I think more than anything it's just emotionally draining. Physically, we've trained for this all year."
Game 2 of the best-of-three championship series is Tuesday night.
"I just told our kids that this is not over yet," said Lady Vols co-head coach Ralph Weekly, whose team won the opener in 2007 before losing the next two to Arizona. Oklahoma did the same thing last season, losing Games 2 and 3 - and the national championship - to Alabama.
"We're still very much alive," Weekly said. "We're facing a very, very good opponent but we're ready to move on to tomorrow."
Shipman lined an 0-1 pitch from Ricketts over the 220-foot fence in straightaway center field to break a scoreless tie in a throwback to the pitching duels of World Series from years gone by.
But the Sooners were able to rally in the bottom half of the inning after second baseman Lauren Gibson dropped Ricketts' popup along the right-field line to allow her to reach second. Brittany Williams followed with an RBI double and Destinee Martinez had a two-out RBI triple before Callie Parsons tied it on an RBI double to left.
Parsons was thrown out trying to advance to third.
"It was phenomenal how we ended up tying that game with just some clutch hits, and it all came in one inning," Sooners coach Patty Gasso said. "Sometimes that's all you need. ... That was one of the most amazing comebacks I've ever seen."
Ricketts retired the Lady Vols in order in the 12th, striking out national player of the year finalist Raven Chavanne to end the inning, before the Sooners struck again. Brianna Turang chopped a double down the left-field line before Chamberlain's blast.
"This is a team on a mission and, man, I've never seen anything like it," Gasso said.
It was the longest outing of Ricketts' career, and she hadn't needed to throw more than seven innings all season as the dominant Sooners had 20 of their games shortened to five innings by the eight-run mercy rule. They led the nation in scoring and earned-run average coming into the World Series and had won five of their first eight NCAA tournament games by the mercy rule while outscoring opponents 82-13.
But they ran into a Tennessee team that had also gone 8-0 in the NCAA tournament to reach the finals. The finals feature all three finalists for national player of the year - Ricketts and Chamberlain for Oklahoma, and Chavanne for the Lady Vols.
Chavanne, a .455 hitter, struck out four times and went 0 for 6. Chamberlain was 2 for 6 and also had a double and Ricketts was 2 for 5, with the 11th-inning popup being officially scored as a double.
The teams combined for just three hits through seven innings, and then both started threatening in the extra frames.
"The key for us, and we're going to spend all night if we have to, is figure out how to do better at the plate," Weekly said. "I think that's the key for us. And I'm sure Patty's doing the same thing."
The Lady Vols got the leadoff runner on in the eighth when shortstop Jessica Vest misplayed Melissa Davin's grounder for an error. She was sacrificed to second before Hannah Akamine drew a four-pitch walk, but Ricketts struck out pinch-hitter Rainey Gaffin before Chavanne lined out to Vest for the third out.
Renfroe then got herself into and out of a tight spot in the ninth, giving up Georgia Casey's leadoff single before throwing into the dirt on Shelby Pendley's sacrifice bunt. She struck out Ricketts before a wild pitch allowed both runners to advance with one out, then walked Brittany Williams to load the bases.
First baseman Melissa Brown fielded Jessica Shults' grounder and got the force at home, then Renfroe struck out Martinez to send the game to the 10th.
"I don't even know what to say," Gasso said, "except I think that was the greatest game I've ever been a part of."