When you only play 30 minutes, the margin for error shrinks and the Philadelphia Eagles found that out the hard way on Monday night in Atlanta.

A missed Cody Parkey 44-yard field goal with 2 1/2 minutes remaining and an egregious drop by second-year receiver Jordan Matthews in the waning moments doomed the Eagles, who dropped their season opener to the Falcons 26-24.

As expected Atlanta star receiver Julio Jones torched the rebuilt Philadelphia defensive backfield, especially early by snaring eight balls for 97 yards and two scores in the first half as Atlanta built a 20-3 lead at intermission.

A Walter Thurmond interception of an ill-advised Matt Ryan pass early in the third quarter shifted momentum and the Eagles came all the way back to take a 24-23 advantage when Ryan Mathews plunged in from a yard out in the fourth quarter.

Bill Davis' much-maligned defense couldn't make that hold up, however, and Matt Bryant's fourth field goal of the night, a 47-yarder with 6:27 left proved to be the game winner.

Jones finished with 141 yards receiving and the two touchdowns, while Ricardo Allen's interception off the Matthews drop sealed things for Atlanta with just over a minute left.

"Our defense stepped up at the end of the game," Ryan said. "Ricardo has worked so hard."

After a slow start Sam Bradford, playing in his first regular-season game in nearly two years, finished 36-of-52 for 336 yards in his Eagles debut but the revamped running game was dismal.

After leading the NFL with over 1,800 yards rushing in Dallas last season, DeMarco Murray mustered just 9 yards on eight carries while his caddy, Ryan Mathews had only 4 yards.

IGNORE THE PRESEASON

The Eagles were so good in practice games that more than a few members of the national media were tripping over themselves to declare the team a legitimate Super Bowl contender even with all the upheavel Chip Kelly unleashed on the roster in a continuity-driven league.

And maybe Philadelphia will turn out to be exactly that but the learning curve is going to be far steeper than expected as evidenced by the team's loss tonight.

The narrative that this was going to be a cakewalk was a flawed one. The Falcons aren't a great team by any means but they often play that way indoors and they proved to be a resurgent group under new head coach Dan Quinn, especially the much-maligned defense, which turned Bradford into a very uncomfortable and inaccurate QB early before the Eagles tempo took over.

SHADY IS SMILING

LeSean McCoy didn't set the world on fire in his Buffalo debut but he might as well have been Jim Brown compared to what Murray and Mathews  were able to muster. In fact Darren Sproles was by far the Eagles best back in Atlanta and that has to change in a run-based offense.

DB REPORT CARD

It was a mixed bag for the Eagles' rebuilt defensive backfield as Jones tortured the group. To be fair though Jones is handful for anyone but the concern is that Byron Maxwell's contract will spawn unrealistic expectations. Good players, and that's what Maxwell is, get overpaid if they reach free agency and that's exactly what happened to the ex-Seattle corner. Maxwell is being paid like he's Richard Sherman and he's not. What he is, however, is a significant upgrade over what was here last year.

At safety Thurmond did struggle with his tackling at times but also flashed his ball skills by picking off Ryan early in the third quarter to get Philadelphia back in the football game.

Perhaps the biggest surprise was that backup safety Chris Maragos was the nickel back, entering the game at safety when Davis used an extra defensive back with with Thurmond or Malcolm Jenkins dropping down in the slot. That unconventional move spoke more to how much rookie Eric Rowe struggled in the preseason rather than anything all that great about Maragos, whose main attribute is being a core special teams player.

O-LINE STRUGGLES

The Eagles offensive line has a big reputation but had its hands full with a bulky Atlanta front featuring 345-pound nose tackle Paul Soliai. And by and large it wasn't the new starting guards, Allen Barbre and Andrew Gardner, who were the problem. Stud left tackle Jason Peters had one of his worst games an an Eagle and center Jason Kelce and right tackle Lane Johnson also had their issues at times with three penalties between them.

ERTZ AVAILABLE

The timetable seemed optimistic but Zach Ertz was able to suit up in Week 1 after undergoing surgery for a core muscle injury in the preseason. The Stanford product wasn't spectacular but his presence is important. Unlike Ertz the other questionable player for the Eagles, backup outside linebacker Marcus Smith did not dress after being limited all week with a hamstring injury. Others who sat included running back Kenjon Barner, offensive linemen Dennis Kelly and Josh Andrews, defensive end Brandon Bair, cornerback Denzel Rice and recently acquired quarterback Stephen Morris.

-John McMullen covers the Eagles and the NFL for 973ESPN.com. You can reach him at jmcmullen@phanaticmag.com or on Twitter @JFMcMullen