But their loss at the hands of the Trojans isn't the end of the world.
"We try to win everyday, and today we didn't," said head coach Sunny Golloway. "We lost and we didn't play well. Right now I think we're going to play a lot looser and focus on getting better and not so much on the [winning] streak and being undefeated."
The 16-0 start tied for the best start to a season by a Big 12 team during the conference's era. The only other team to do this was the 2005 Texas Longhorns, who won the national title that year.
OU took two of three games from the Trojans over the weekend to improve to 16-1 before heading out to Tempe, Ariz., to take on Arizona State in two midweek games and then opening conference play next weekend against Texas A&M.
The Sooners won the series opener 11-4 behind another seven-inning effort from senior pitcher Michael Rocha and some timely hitting after falling behind 3-0 going into the bottom of the fourth inning.
Rocha, who boasts a 4-0 record and 1.20 ERA, struggled early on but gained his composure in the fifth inning before throwing three shutout innings to end his day.
"Today was a grind," Rocha said. "It was more about being mentally tough and getting my offense the best chance they'd have to score. It was basically how tough are you today? We came out with a victory, so you can't be disappointed."
But after exploding for double-digit runs for the eighth time, the bats went silent.
The Sooners collected just nine hits – seven Saturday and two Sunday – in the series' final two games and was held to two runs.
Overton went 6 1/3 innings without allowing a run following senior pitcher Bobby Shore's one-inning performance to start the game. Shore was lifted because he was inconsistent in the strike zone and was getting hit hard.
Although junior closer Ryan Duke was credited with the victory in his first game back from suspension, Overton pitched well enough to work his way into the weekend rotation.
Reine drove in the Sooners' only two runs by getting hit by a pitch with the bases loaded to tie the game in the third and drove in the winning run in the eighth by plating junior Erik Ross from third on a hard grounder to second that wasn't fielded cleanly.
But that run was the last for the Sooners during the weekend. Trojan pitcher Calvin Drinnen held OU's bats to two hits en route to a complete-game shutout.
"He did a great job early on," Golloway said. "But once it got to be 4-0 he pretty much – I thought – from the sixth inning on coasted. It was a bad mix for us offensively today."
The last time the Sooners were shut out was against Texas in a 2-0 game at home on April 2, 2010.
The Sooners didn't get a good outing from junior pitcher Burch Smith, who gave up four runs in 4 2/3 innings, and the bullpen couldn't hold down the fort in the late innings when the team could have potentially mounted a comeback. The bullpen allowed one run in the eighth and two runs in the ninth.
Norman is nothing like Pleasantville where the home team never loses. It is better to lose now than it is during conference play, Golloway said.
"I'm not so sure that maybe in the long run – and we'll know down the road – that this wasn't the best thing for us," he said after snapping an 18-game home winning streak dating back to last season. "Clearly if you're going to lose a game I'd rather it be here than in the Big 12 conference."
The Sooners return to action Tuesday against Arizona State. Senior pitcher Bobby Shore and redshirt freshman pitcher Jordan John should be on the mound for that two-game set.