Nebraska scored the game's only run when designated player Tatum Edwards blasted a solo shot just inside the left field foul poll in the top of the fifth.
OU had its chance to tie it in the seventh but designated player Keilani Ricketts struck out, stranding runners on first and second to end it.
The Sooners had a chance to take the lead earlier in the game when they had runners on second and third with nobody out in the fourth, but center fielder Destinee Martinez grounded to short, shortstop Javen Henson lined out to the pitcher and first baseman Lauren Chamberlain flew out to right to halt the threat.
Sooner pitcher Michelle Gascoigne, who tossed a complete game with only one earned run, while striking out seven and walking just one around two hits, suffered the hard luck loss.
Nebraska's Emily Lockman became the first opposing pitcher to beat the Sooners.
OU took the first game of the doubleheader between the squads 10-3 earlier in the day.
Catcher Jessica Shults got OU on the board with an RBI groundout, and Ricketts followed with a two-run single to make it 3-0 in the third.
The Cornhuskers notched things up in the fifth with a hit-by-pitch and two-run error.
But OU came back with a crooked seven-spot in the bottom half to win going away.
Martinez recorded an RBI single, right fielder Brianna Turang forced a bases loaded walk, then Chamberlain smacked a two-run single and Shults singled to score three more.
Shults led the team with three RBI in the contest.
OU hopes to get back to its winning ways with a 12 p.m. CT Sunday date against Houston.