"I was just trying to get a base hit the other way, and he gave me a good pitch and put a good swing on it," Oberste said.
Before that, though, the Sooners collapsed a bit to need the heroics.
Saturday it was the opposite with OU storming back from a six-run deficit; this time it was Hofstra plating three in the latter stages to make it interesting.
Moments after Sooner right fielder Max White misjudged a wind-altered ball at the warning track, Pride second baseman Austin Nyman doubled into the left field corner to bring Hofstra within 4-3.
Designated hitter Bryan Verbitsky followed up with an RBI single to tie it.
But reliever Jake Fisher, who surrendered the three earned runs along with three hits and a walk in that troublesome eighth inning, eventually worked his way out.
Closer Robert Tasin tossed a scoreless ninth to grab the victory.
"You know what? Fish has got to do a better job in the middle," said OU head coach Sunny Golloway. "Tasin did a good job on the back end this weekend, and we'll just keep moving forward."
Outside of the ball he somewhat misplayed, White put together a very nice game, going 3-for-4 with two RBI, including an RBI single in a two-run first.
Oberste, with the big jack, finished 1-for-4 with four RBI and a run scored.
Second baseman Jack Mayfield, who scored the decisive run on the walk-off, also had a pair of hits on four plate appearances and scored a couple of runs.
"We kept our heads straight and the leadership and experience really pulled us through this one," White said.
The Sooners took the early 2-0 lead on White's RBI single and a Oberste's sacrifice fly to right.
Hofstra cut that deficit in half in the top of the second when catcher Matt Reistetter scorched an RBI single up the middle.
OU took a 3-1 lead it would carry most of the way when, in the bottom of the fourth, left fielder Hunter Haley singled home third baseman Garrett Carey.
The Sooners added another in the seventh on White's second RBI single of the day.
Starter Corey Copping, although he finished with a no-decision, allowed just one earned run in seven innings while surrendering just a pair of hits and walks and striking out four in his career debut.
"I mean, I'm proud of myself," Copping said. "First game as a freshman, the environment was great. Way different than high school. I mean, I'm just glad I was able to start. I thought I did really good."
"He was scheduled to be the spot starter, which would have went Saturday in game two," Golloway said. "Because right now it's Overton, Gray on and then who was gonna start Sunday. And it was Waltrip earlier and then we switched it and right now Coppin will start the game on Sunday. Our one, two, three is that. Billy's gotta earn that spot back in there and he'll try to do that. But the freshman's pretty special."
OU finished with seven runs on nine hits, committing just one error after doing so at least three times in each of the first three games.
"Defense and pitching wins games," White said. "That's what we always talk about."
That, as it has all series, plagued the Pride again Sunday, as they committed four errors while scoring their output on five hits.
The Sooners will get back to action with a midweek series against Arkansas-Pine Bluff, slated for 3 p.m. Tuesday first pitch at L. Dale Mitchell Park.