CATHEDRAL CITY, Calf. -- Tennessee star freshman Caylan Arnold outdueled Oklahoma's Paige Parker as the Volunteers held off a late rally to defeat the defending national champions, 2-1, on Thursday evening at the Marry Nutter Classic.

Entering the seventh inning with a 2-0 lead, No. 15/13 UT had to hold off a rally by the fourth-ranked Sooners (7-3). With two outs and runners on the corners, a throwing error extended the inning and allowed Caleigh Clifton to score and cut the Tennessee lead to one. One batter later, Megan Geer came up with a huge catch in right field to end the game, just snagging the ball before it hit the turf.

Arnold was the story once again for the Vols, tossing a complete game gem to improve to 5-0 on the season. The Maryville native scattered just four hits and surrendered a single unearned run while striking out four. Oklahoma pitcher and 2016 NFCA All-American Paige Parker was also solid in the circle, allowing just five hits while recording eight strikeouts in a complete-game effort.

Another freshman was the hero for the Big Orange offensively as Chelsea Seggern drove in both Tennessee runs with a single to right field in the second inning. Seggern came up clutch with a two-out single on a 3-2 pitch to score Meghan Gregg and Geer and put the Vols ahead 2-0 early on. The Texas native also had a double in the top of the seventh and finished with two of the Vols' five hits for the game.

The win avenged a 9-0 loss to the Sooners last season in Knoxville and helped UT improve to 11-0 on the year. It was also the first win for the Vols this season over a ranked opponent.

Aubrey Leach, Gregg and Geer had the other three hits for Tennessee while four different Sooners all recorded a hit. With Gregg's single in the second inning, she extended her hit streak to eight games.

THE REAL DEAL: Tennessee freshman pitcher Caylan Arnold has been nothing short of spectacular over the first three weeks of the season. The Maryville native went the distance and did not allow an earned run to No. 4/5 Oklahoma to improve to 5-0. Arnold has yet to give up an earned run this season and showed incredible poise to get the final out with the winning run on second base.

SEGGERN COMING UP CLUTCH: Freshman third baseman Chelsea Seggern came up with the biggest hit of her young career. The Thrall, Texas native laced a two-run single into right field in the top of the second to give the Vols a 2-0 lead. Seggern had two of Tennessee's five hits in the win over the Sooners after also hammering a double to right center in the seventh inning. She now has eight RBIs on the year.

BEATING THE BEST: Today's win over the Sooners was the first over a ranked opponent for Tennessee this season. The Vols have now won their last three contests against teams ranked in the top five.

UP NEXT: The Vols are back in action tonight against UC Santa Barbara. First pitch is slated for 11 p.m. ET and the game can be seen live on FloSoftball.com.