Seventeen points should be enough.

Staked to a 17-0 lead with 33 seconds left in the third quarter, the Eagles defense took the field against a Panthers offense that had gained just a total of 106 yards and had punted on all five of its previous possessions.

The unit had systematically shut down quarterback Cam Newton and the Carolina offense. But what happened over the next 15-plus minutes was a collapse of epic proportions, especially at the NFL level. The Eagles offense could have done more in the fourth quarter, but Jim Schwartz's defense was, ultimately, culpable for the 21-17 loss.

"We blew it on defense," defensive end Chris Long said. "Offense held up their end of the bargain, possessed the football the whole game. We blew it at the end."

Defensive tackle Fletcher Cox called it the worst loss of his career. Other Eagles defenders weren't as reactionary. But there were few answers or explanations why they have now coughed up two double-digit second-half leads this season.

Sunday was much worse than the Oct. 1 overtime loss to the Titans, though.

>> GRADING THE EAGLES: Pass defense gets an 'F' in loss

"We play hard, but we just have to finish the game," defensive end Brandon Graham said. "We can't keep giving away games, especially when we have them. I mean, that's a good Carolina team. We knew it was going to be 60 minutes."

But they were only 45-minute men. The Panthers scored touchdowns on three straight drives, gained 236 yards, and converted a long fourth down that should haunt the Eagles, although the same could have been said about the long fourth down conversion they surrendered to Tennessee three weeks ago.

Newton became the opposite quarterback he was through three quarters, when he completed just eight of 15 passes for 59 yards. The Panthers went to a quick-strike, no-huddle offense and Schwartz and his players did little to counter their effectiveness.

It was a death by a thousand cuts as Newton connected on 17-of-24 attempts for 210 yards. The Eagles, who had been susceptible to deep passes in their first six games, didn't allow a pass over 16 yards until midway through the fourth quarter.

But the Panthers realized they weren't going to be able to move the ball unless they found a way to neutralize the Eagles' pass rush.

"They were running a lot more quick game," Graham said, "getting the ball out."

>> MARCUS HAYES: Panthers' Eric Reid — Colin Kaepernick's closest ally — calls Eagles' Malcolm Jenkins a 'sellout'

Schwartz played more man defense down the stretch. Safety Malcolm Jenkins said that it was to handle Newton's scrambles. But the coverage created space underneath, at times, for running back Christian McCaffrey (six catches for 51 yards in the game) and receivers on shorter routes.

"I think catching them in man coverage and having their backs to the line of scrimmage a couple times," Panthers coach Ron Rivera said, "really helped to make some of those quick passes a little more effective."

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That may explain several completions, but on the Panthers' first drive of their comeback, Newton had all sorts of time when he found receiver D.J. Moore for 16 yards on third-and-3. A play later, Carolina caught the Eagles with misdirection when receiver Curtis Samuel scooted 14 yards into the end zone on an around.

Hat tip to Panthers offensive coordinator Norv Turner for the design and call on that play. But there were also moments when Eagles defenders either didn't carry out their assignments or make the necessary plays.

>> LESSONS FROM A STUNNING LOSS: The Eagles need running and defensive backs to protect their leads | David Murphy

Cornerback Ronald Darby bit on a double move and Devin Funchess had himself an 18-yard touchdown that whittled the Eagles lead down to 17-14 after a two-point conversion. And then after the Eagles offense went three and out – Doug Pederson, Carson Wentz and the offensive unit shouldn't escape criticism – cornerback Jalen Mills was targeted on fourth down.

Newton tossed three straight incompletions to set up fourth-and-10 on the Carolina 31 with just over two minutes left. Schwartz rushed only four, as he had for most of the game, and the Eagles dropped into man coverage with safety Avonte Maddox over top. Linebacker Jordan Hicks spied the quarterback.

Newton didn't have anything initially, but as he stepped up and shed Graham, receiver Torrey Smith broke free on a dig route vs. Mills.

"Kind of got a little shove [from Smith]," Mills said, "and ended up slipping."

>> LESSONS FROM A STUNNING LOSS: The Eagles need running and defensive backs to protect their leads | David Murphy

Even if Mills could be excused for slipping or having to cover that long – Smith was beyond the first down marker after the catch – his tackle attempt was lacking. The former Eagles receiver turned up field and gained an additional 20-plus yards.

"We've got to, as players and coaches, make sure we're putting our guys in position, and then secondly, we've got to execute the play," Pederson said. "Flat-out, this is a players' game. Players have to make plays."

>> READ MORE: Doug Pederson says 'the pressure is off' and 'anything is possible' following loss

Two plays later, on third-and-2, McCaffrey picked up 22 yards down to the 4-yard line when Hicks was rubbed out on a short pass out of the backfield. And on third-and-goal at the 1, tight end Greg Olsen was uncovered as he released into the end zone. The Panthers had reeled off 21 straight points.

The Eagles entered the game with the No. 1 red-zone defense, having allowed only eight touchdowns on 24 possessions inside the 20. On Sunday, the Panthers went 3-for-3 down there. The unit was shorthanded in the secondary with cornerback Sidney Jones sidelined, but Dexter McDougle, signed just last week, seemed to fare well in the slot.

Could Schwartz have blitzed more? The front four had success early, but maybe they needed more help at a certain point. But there were few definitive answers afterward. Perhaps Schwartz will shed more light on his unit's unfolding when he speaks Tuesday.

His players offered little rationalization afterward.

"I'd love to answer your question with something substantive," Long said, "but I have no [bleeping] clue."

>> READ MORE: Dexter McDougle joined the Eagles on Tuesday. He started on Sunday.

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