FLOWERY BRANCH — The Atlanta Falcons didn't have much to be proud of Monday.

Even defensive end Kroy Biermann, who scored Atlanta's only touchdown in a 30-12 season-opening loss at Chicago, was in a somber mood.

"We've got some stuff to work on," Biermann said. "They got some runs on us and obviously some screens. There are some issues there that need to be cleaned up."

With Philadelphia (1-0) and former Falcons quarterback Michael Vick visiting the Georgia Dome in six days, coach Mike Smith said Atlanta (1-0) can't wait long to fix mistakes on offense, defense and special teams.

Other than Matt Bryant's 2-for-2 afternoon on field-goal tries, the Falcons flopped hard in their opener:

The defense missed enough tackles for a month's worth of bad highlights and created just one takeaway, Biermann's interception return early in the fourth quarter.

Quarterback Matt Ryan, who was sacked five times and hit six others, combined with running back Michael Turner for three turnovers. The offense, despite 386 net yards, went 0-for-2 in red-zone chances and converted only four of 13 third-down opportunities;

Three of the team's nine penalties were committed by the coverage and return units.

Smith, a fourth-year head coach who spent nine NFL seasons as a defensive assistant, was particularly disappointed in the missed tackles.

Chicago had six plays of 23 or more yards. Two screen passes, one a first-quarter touchdown by running back Matt Forte and a second that receiver Devin Hester took to the Atlanta 1 in the third period, each were caught behind the line of scrimmage and covered 50-plus yards.

"Fundamentally, tackling is something you have to be proficient at," Smith said. "We were not very proficient in our tackling, and that led to explosive plays."

Pro Bowl defensive end John Abraham had two of Atlanta's five sacks, but the pressure was inconsistent on Bears quarterback Jay Cutler most of the afternoon.

"We didn't match their defense and play, I guess, like they did," Abraham said. "They came out and created some turnovers early, and we created one turnover late in the game. The game was kind of out of reach by then."

Missed assignments against the run and pass were problematic, too.

"They got on a run very early," Smith said. "They converted on a third down with a flag route. We were in a blitz zone and we had a miscommunication, so it was basically an uncovered guy, and then we had a guy drop coverage on a third-and-13 as well."

Offensively, the score was so lopsided midway through the third quarter that Atlanta had to abandon the run. The Falcons ran just five plays on the ground in the second half and had few chances to make use of Turner, a two-time Pro Bowl selection over the last three seasons.

"When you have a defensive line that basically only has to defend one thing, it makes it tougher for your offensive protection to hold up," Smith said. "But we've got to improve that."

The performance was a huge disappointment by Falcons, who returned 19 starters from a club that went 13-3 last season and earned the NFC's No. 1 playoff seed.

Pro Bowl right tackle Tyson Clabo was in a terse mood as he described his frustration. Using more colorful language, he said when an NFL team loses the turnover battle, this is what happens — you get your butt kicked.

"We've got a lot of work to do this week because obviously it's not getting any easier," Clabo said. "The Eagles are a good team."