Down 25-24 past the halfway point in the first half when it seemed like things were shaky, the Sooners surged on a 15-0 run to take a commanding lead and never looked back.
And those last eight minutes of the first half really set the tone for the rest of the game.
"It was better," Coale said. "It was like [our nerves settled down]," Coale said.
OU finished the first half on a 28-14 run to take a 52-39 lead into the break.
To start the second half, the Sooners picked up right where they closed the first frame, but they were much more poised than the first 20 minutes.
"The first half we were way wound up, [and we] played with much greater rhythm and much greater discipline in the second half," Coale said.
Senior forward Amanda Thompson picked Mercer forward Amber Coleman's pocket on the opening possession of the second frame, and OU junior guard Danielle Robinson finished off the possession with a jumper.
And the Sooners only extended their lead from there.
When Mercer finally calmed the Sooners down, it was too late, as OU used a huge 35-9 run throughout the first 10 minutes of the second half to put the game away.
"Yes, I would say there was a stretch, probably the first—I'm not good with time looking back at the minutes of the second half—but maybe the first eight, nine minutes of the second half, I thought we really controlled the game at both ends of the floor and playing the way we wanted to play," Coale said.
Senior forward Nyeshia Stevenson added 10.
For Mercer, redshirt freshman guard Lindsey Lowrie was the leading scorer, as she was 4-for-8 from behind the arc en route to a 16-point outing.
But even though the Sooners cruised to victory, there were some obvious areas of concern.
OU turned the ball over 19 times in the contest.
"That's way too many for this team," Coale said. "We can't do that, but the three that Joanna [McFarland], she's a freshman, she's terrified. She's, her mind's going seven thousand miles per hour. That's going to happen. [But] our two point guards combined for nine. That's unacceptable."
Robinson had four, and sophomore point guard Jasmine Hartman turned it over five times.
"Yeah, I definitely was going too fast," Robinson said. "Most of mine were [because of] going to fast."
Regardless, though, the Sooners fought through their miscues to get the first victory of the year.
OU next plays at 1:30 p.m. Sunday at Georgia.