"It's been the offense as a whole," Renner said Monday. "Everybody's stepping up their role and just done their job. I think we were putting too much pressure on ourselves early in the year, trying to control everything and doing things that were out of the realm of our job description - me included."
Much of Renner's success started in the second half of the 39-34 loss at Louisville, where he finished with a career-high 363 yards and five touchdowns. Renner followed that by completing 27 of 43 passes for 321 yards and two scores as North Carolina (2-2) beat East Carolina 27-6.
Renner has thrown 78 straight passes without an interception heading into Saturday's home game against Idaho.
First-year coach Larry Fedora, who brought the offense with him from Southern Mississippi, said Renner is learning on every snap.
"Every time a safety moves and rotates down, and he gets to see that and see it live and see himself do it, it's just a learned experience and something he can continue to work on," Fedora said. "It's still about managing the game, which is moving the chains. Moving the chains is the most important thing he's doing - and taking care of the football."
Offensive coordinator Blake Anderson said Renner started the year by holding onto the ball too long and not getting the offense to the line quickly enough. He even described Renner as "picking daisies" after a long pass play in the opener against Elon.
Since then, Anderson said, Renner has made better decisions, been more effective in avoiding rushers and made the right reads on checkdown passes to keep the chains moving.
"I think we've got a lot of improving left in us, which is encouraging because we have done good things throwing the ball the last couple of weeks," Anderson said. "I think as receivers get more comfortable and Bryn gets more comfortable, we'd like to think we can improve even more on what we're doing."
Still, the biggest complaint for Fedora and Anderson is the pace. Anderson said he'd ideally like the snap to come with anywhere from 24 to 28 seconds left on the play clock, with a rough target of getting 80 plays.
The Tar Heels are averaging about 72 plays this season, though they slowed things down in the second halves against Elon and East Carolina with comfortable leads. Anderson said things have improved but it's still like "watching paint dry out there for me right now."
Anderson said Renner's next step is to make the handoff or the throw, then automatically run to the line to get the offense lined up without having to think about it.
Renner said he's up for the challenge of trying to please his demanding coaches when it comes to tempo.
"I think we're building toward that, but I think every week it's a point in the locker room and a point from the coaching staff to just get the tempo started and get us going," Renner said. "I think we've improved light years from where we were for Elon, but it can always get better."