Mayfield and Darnold are in what the Panthers call an "open'' competition for the starting job. Neither made a big deal about who started after Saturday's 23-21 win over the Commanders.
"It was my turn to start," said Mayfield, who for the most part has been alternating with Darnold on who works with the first team in practice. "Just take it one day at a time. Don't be critical of ourselves and try to get better."
Said Darnold: "For me personally, it's doing everything I can with the plays that I have. That's how I've got to take it at this point."
Mayfield went 4-for-7 for 46 yards in his only drive that ended with a 41-yard field goal. His biggest mistake was a fumbled snap in the red zone (19-yard line) that left him with a third-and-14 pass he didn't complete.
"Obviously, gotta clean up the center-QB exchange," Mayfield said. "That was 100% my fault. Points are always good on the opening drive, but it's frustrating not getting into the end zone."
Darnold took over at the Washington 19-yard line on his first series after the defense recovered a fumble. He needed only three plays to get Carolina into the end zone, the third an 8-yard pass to wide receiver Rashard Higgins, who was one of Mayfield's favorite receivers in Cleveland the past four seasons.
Darnold put great touch on the touchdown in an area he struggled last season. He completed just 54% of his passes in the red zone in 2021 and he had a Total Quarterback Rating of 34.
Darnold got a second series since his first was short. He threw away his only pass attempt under pressure on third down.
"It was a good first drive, and that second drive ... it wasn't the best," Darnold said on the television broadcast.
Mayfield started fast, completing his first two pass attempts and four of his first six to move Carolina to the 19. The drive bogged down on his fumbled snap, but overall he was in command of the offense against Washington's first-team defense.
Mayfield and Darnold split reps with the first team in the first phase of training camp at Wofford College in Spartanburg, South Carolina, that ended on Wednesday.
His mantra since camp opened has been "when we know, we know.''
But Mayfield was first up in Thursday night's FanFest at Bank of America Stadium, and now he has started the preseason opener, signs the team is leaning toward him.
Rhule, however, didn't make a big deal about Mayfield starting.
"That was just for today," he said. "Just for today. Both guys played well in terms of production."
Carolina acquired Mayfield last month in a trade with the Browns, who replaced the top pick of the 2018 draft with Deshaun Watson.
Both Rhule and offensive coordinator Ben McAdoo called Mayfield's progress the first two and a half weeks of training camp "impressive." Mayfield said Saturday his grasp of McAdoo's system is "night and day."
"I feel a lot more comfortable," he said. "That permeates throughout our offense."
Corral, despite leading Carolina to the winning field goal thanks to a couple of Washington penalties, said he had to have better communication regardless of who he's playing with.
"We always say we want complete, clear and concise communication," the third-round pick said. "We were just all over the place out there, and that's on me."