The Jacksonville Jaguars were the NFL's biggest surprise in Week 1 — for a half.

But after taking a 17-0 lead at Philadelphia, the Jaguars faltered mightily after the break and looked a lot like the team that lost its first eight games last season by double digits.

The running game was mostly nonexistent. The passing game was filled with batted balls, errant throws and drops. The defense gave up several big plays, on the ground and through the air. The result was a 34-17 loss to the Eagles in the season opener that will be remembered more for the way it ended than how it began.

"It feels like, 'What happened? We're a ways away,'" coach Gus Bradley said Monday. "But we're really close. We have to take care of these things. We can no longer find these things acceptable, but I liked our demeanor in the room. They take responsibility and they understand as well."

The Jaguars (0-1) couldn't have looked much better in the first half.

They scored touchdowns on two of their first three drives — it took Jacksonville 36 drives to find the end zone in 2013 — and were dominating both sides of the ball.

Chad Henne completed 12 of his first 17 passes for 167 yards, with a pair of touchdowns to undrafted rookie Allen Hurns. Jacksonville's defense, which ranked last in the league in sacks over the last five years, took down Nick Foles five times, held LeSean McCoy to 38 yards on 10 carries and forced three turnovers.

"It's pretty clear we went out in the first half and played really, really good football," Bradley said. "To us, that's the standard. We set the standard ... and we didn't do that in the second half."

The Jaguars will try to regroup this week before playing at Washington (0-1).

Jacksonville does have this going for it: the collapse wasn't nearly as bad as last year's debacle, which was the worst season opener in franchise history. The Jaguars managed 178 yards, punted 11 times and allowed six sacks in a 26-point home loss to Kansas City.

The beatdown set the tone for Jacksonville's 4-12 season, which included eight lopsided losses to start the season.

The latest opener had plenty of positives — just none after halftime.

"What we did the first half was good, but you want to be able to sustain that for four quarters," guard Zane Beadles said. "With a young offense and a group that hasn't played a lot together, you're going to have that. But that's no excuse for us. We need to go out there and expect the highest effort from ourselves."

Although Jacksonville lost some momentum late in the second quarter with a missed field goal and a blocked field goal on consecutive drives, the real turning point came with a third-quarter mistake.

Bradley said Monday he should have taken a timeout before a fourth-down conversion that sparked Philadelphia's comeback.

Darren Sproles went untouched through a huge hole on a fourth-and-1 play near midfield and ran 49 yards for a touchdowns.

The Jaguars were late lining up on the play and the Eagles snapped the ball before the defense was set. The Jaguars were without middle linebacker Paul Posluszny, who left the game earlier in the drive with a knee contusion, and had backup J.T. Thomas calling the defensive signals.

Thomas had just finished calling the defense when the Eagles snapped the ball.

"I made a mistake," Bradley said. "I saw we had different personnel in the game, some new guys. I felt like we got the call in, but in hindsight I looked back at it and I should have stepped up and called a timeout there."

The play was the first of 34 unanswered points for the Eagles, who essentially ended up replacing Jacksonville's surprising first half with a more expected final result.

"When a team loses momentum in the first half like we did, it's on everyone to work hard and try to get it back," running back Toby Gerhart said. "You need to make a play, make a play to get the momentum back and stop the downhill tumble."

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