Too many mistakes.

Finally, it all became too much for the 49ers to overcome. 

San Francisco turned the ball over four times in opposing territory, failed to force a takeaway and allowed the Falcons to extend multiple drives via penalties and missed assignments.

Despite scoring the game’s first two touchdowns, the Niners allowed Atlanta to score on four consecutive possessions and were handed their first loss of the season, 26-20.

The defeat sends San Francisco into its bye week at 6-1, still on top of the NFC West.

Our report card:

Quarterback: C

Brock Purdy got the ball to begin the third quarter in an unfamiliar position: Trailing 19-14.

Purdy had been asked to author just one second-half comeback this season, when he rode Mike Evans down the field for the go-ahead score Week 5 in Seattle. Without Evans at his disposal against the Falcons, it went differently this time around.

Michael Penix Jr. led Atlanta down the field on its first possession of the second half, and the next two chances Purdy got to retake the lead ended in an interception and a fourth-down sack.

It looked like Purdy was trying to throw the ball away after being forced out of the pocket on second-and-14 from the Atlanta 25, but it went straight into the arms of Jessie Bates III.

The 49ers were back in Falcons territory on their next trip down the field, but after a touchdown completion to Jordan Watkins was overturned, Purdy missed a third-down throw to Christian McCaffrey and succumbed to the pass rush on fourth down, giving the ball right back.

Including Kaelon Black’s fumble on the 49ers’ final drive of the first half, San Francisco drove into Atlanta territory on three straight possessions that produced zero points.

The 49ers had crossed midfield again with less than 3 minutes left, trailing by six, when Purdy was picked off for a second time by rookie linebacker Kendall Daniels.

Purdy had thrown only two interceptions through his first six games; he was picked off twice against the Falcons for his first multi-interception game since Week 12 of last season.

Running backs: B

McCaffrey spent most of the second quarter in the medical tent with a thigh injury but otherwise was the 49ers’ only viable offensive weapon besides tight end George Kittle.

He touched the ball six times for 69 yards on the 49ers’ opening drive but gained only 31 yards the rest of the game for an even 100 from scrimmage.

With McCaffrey sidelined, Kaelon Black broke off a 30-yard touchdown scamper that put the 49ers up 14-3 on the first play of the second quarter. But he also coughed up a fumble on the Niners’ next trip into Atlanta territory — one play after third-string running back Jordan James put the ball on the ground and was saved by his teammate falling on it.

Wide receivers/tight ends: C

For the first time this season, the 49ers had to navigate a game without Evans. They were also without Deebo Samuel, Demarcus Robinson, De’Zhaun Stribling or Ricky Pearsall.

Brandin Cooks and Jordan Watkins started the game as the 49ers’ top two receivers, but it took until the 8:36 mark of the second quarter for a receiver to even record a target, let alone a catch. 

Watkins eventually made his presence felt in the second half, but he was unable to hang on to a difficult catch over C.J. Henderson in the end zone. Watkins got both his feet down but was determined not to have possession of the ball when he hit the ground.

Kittle also had trouble hanging onto the ball after hauling in his team-leading eight catch of the day, allowing the ball to be punched out for the 49ers’ fourth turnover in Falcons territory.

He and McCaffrey combined for 149 yards through the air; seven other 49ers to be targeted by Purdy combined for 139 yards. In his 49ers debut, Christian Kirk wasn’t one of them.

“I was really proud of a lot of guys,” coach Kyle Shanahan said. “I thought our wideouts stepped up. Jordan Watkins made some big plays. We ran the ball really well. We had one punt in the game.

“But when it comes down to the turnovers, we’ve got to protect the ball better.”

Offensive line: C+

After going four weeks and 123 dropbacks without allowing an opponent to get to Purdy, the 49ers offensive line has surrendered multiple sacks each of the past three games.

The most consequential came with San Francisco facing a fourth-and-10 from Atlanta’s 23 early in the fourth quarter. Purdy was bum-rushed and went down almost instantaneously, giving the ball back to the Falcons trailing 26-14 with 11:30 to play.

Defensive line: D

The 49ers sure missed Nick Bosa, who was ruled out for the fifth consecutive game.

Not only did they fail to record a sack of Penix, they didn’t lay a single hit on the Falcons quarterback. Penix was regularly able to roll outside the pocket on the rare occasions the 49ers’ pressure got home, including on his touchdown pass to Kyle Pitts Sr. that put Atlanta up 19-14.

The Falcons gave the 49ers a gift when a wide-open Jahan Dotson dropped a pass on third-and-4 around midfield. But Osa Odighizuwa returned the favor by jumping offsides on fourth down, allowing the Falcons to kick a field goal and cut the lead to 14-12 at halftime.

“It was a big turning point,” Shanahan said. “That allowed them to lap us. Because they got the ball out of the half and went down and scored. Gained 10 points without us touching the ball.”

Linebackers: B

Bijan Robinson wasn’t the reason the 49ers lost, which is a credit to a linebacking corps that got Dre Greenlaw back from a one-game suspension. Fred Warner got to Robinson in the backfield on third-and-4, forcing the Falcons to settle for a field goal on their opening drive, and Jaden Dugger wrapped up the All-Pro for a loss of three on a screen pass the next drive.

Robinson put up 122 yards from scrimmage on 25 touches, but the Falcons managed only 82 total yards on the ground despite handing it off 29 times.

Defensive backs: D

Upton Stout was questionable with a shoulder injury, and Ashtyn Davis took the lion’s share of the snaps at nickelback. It was Jack Jones who became a regular target of Penix.

Jones was beaten multiple times and committed an unforgivable pass interference penalty that bailed out the Falcons after a holding penalty had backed them up in a second-and-20.

Nine different Falcons caught passes from Penix, who operated at will under little duress from the Niners’ defensive line, allowing his receivers to get open. 

Penix completed 25 of 34 passes for 213 yards and three TDs. It was the first game this season an opponent has posted a better passer rating than Purdy (118.9 to 75.4).

Special teams: F

An ongoing problem area for the 49ers reared its head again against the Falcons.

Kicker Eddy Pineiro missed his fourth extra point of the season after the 49ers pulled within 26-20 late in the fourth quarter. Before that, their kick return unit allowed Zachariah Branch to run one back 60 yards to the San Francisco 36 and Khalil Herbert to take one 38 yards.

Black appeared to be in the 49ers’ plans as a return man alongside James, but they had to turn back to Jacob Cowing once McCaffrey was injured and Black’s offensive role increased.