CHARLOTTE — Panthers head coach Matt Rhule said Monday he was "disappointed, but we're not discouraged" after losing the opener to the Browns, primarily because of how different they looked at the beginning of the game from the end.

The Panthers trailed 20-7 midway through the third quarter and came back to take the lead inside the final two minutes, and that progression gave him something to hang onto — while acknowledging the early mistakes that got them in that hole.

"Every coach is upset with the result of the game," Rhule said. "At the same time, to play that badly on offense in the first half, and still came back and had a chance to win the football game. On defense, so many plays we want back and still have a chance to win the game. So we have to have a really good week, and we have to play much better.

"I think who we were in the fourth quarter is who we'd like to be. We just have to do it for 60 minutes. When we do that, we'll be a good team."

The slow start on offense was clearly a problem, as they gained 21 yards on their first 20 plays. Rhule said there was a certain point where they stopped trying to play against what the Browns were doing and focus on the plays they liked best "because we were so out of whack."

"Once they got into a rhythm offensively, we saw a lot of good things," Rhule said. "But the detail wasn't up to our standard. We were a team last year, for all the things we didn't do well, we were one of the top teams scoring the first drive or early in the game.

"We want to get better as the game goes on; we just have to start a lot faster."

While that lack of early cohesion opened him up to questions about the decision to make Baker Mayfield and Sam Darnold compete for the starting quarterback job in camp, Rhule said the larger decision-making process made it important to him.

"I think the starting competition was what it was," he said. "I can't go back. We had to do what was right by the team and make sure who our quarterback was. Yesterday was one of 17."

— The run defense will be a topic again this week, since Giants running back Saquon Barkley ran for 164 yards and a touchdown against the Titans Sunday (while the Browns were running for 217 as a team against the Panthers).

Rhule said there were alignment errors during the game, which were disappointing, but he also mentioned 17 missed tackles, and 190 yards allowed after first contact, both numbers that were egregiously high.

He also pointed to five defensive penalties which extended drives, and when you're playing this many snaps this early in the season (the Browns had 80 offensive snaps to the Panthers' 53), you can't afford that.

— Center Pat Elflein said the five fumbled snaps on exchanges with Mayfield against the Browns were due to "poor execution" on his end.

One day after Mayfield assumed responsibility for the miscommunicated snaps in his postgame comments, Elflein also took the blame when talking to reporters.

"I feel like (with) the center-quarterback exchange, it's on both," Elflein said. "You've both got to get that right."

Elflein said he and Mayfield addressed the issue and that working on placing the ball directly in the center of his quarterback's hands will be a focus for him ahead of this week's matchup against the Giants.

"We're going to work on it at practice," Elflein said. "We're going to move on, learn from the game, learn from those mistakes, really get back to work and focus on New York. That's really the only thing you can do now."

The Panthers recovered all five of the fumbled snaps, and running Christian McCaffrey took one of them downfield for a 28-yard gain. Rhule said Monday that some of the botched snaps hit Mayfield directly in the hands, the one recovered by McCaffrey was low, and that the snap issues between Elflein and Mayfield didn't show up in practice before the game.

Elflein said he did not attribute the miscommunicated snaps to the quarterback competition between Mayfield and Darnold, which was held during training camp. Both signal callers took snaps with the first- and second-team units evenly until Mayfield was officially named the starting quarterback on Aug. 22.

"Baker and I just have to get on the same page," Elflein said.

— Rhule said the team came through the game largely healthy, though there's some concern about the status of veteran return man Andre Roberts.

Roberts finished the game but is dealing with a knee issue. He missed some preseason time as well, but he took all the punt and kickoff returns Sunday. Rhule said they're still awaiting some test results on the 34-year-old.

"I would err on the side that I'd be discouraged we'd have Andre this week," Rhule said.

If he can't play, Rhule said they'd likely let Shi Smith return punts, and Chuba Hubbard and Laviska Shenault could be options on kick returns.

— Even though rookie left tackle Ikem Ekwonu gave up a pair of sacks to Myles Garrett, Rhule said a closer look at the tape revealed that it might not have been as egregious a day as it appeared during that two-snap span.

He said on the first one, there should have been a better chip block to help Ekwonu. On the second, it was a three-step drop that Mayfield should have gotten out a little quicker.

"Some of the big 'Oh my gosh' moments for Ickey weren't maybe quite as bad, and he hung in there; he had some good snaps too."