PHILADELPHIA -- The Philadelphia Eagles' defense was pitching a shutout for three-plus quarters. In fact, it was the first time the Carolina Panthers had been blanked heading into the fourth under quarterback Cam Newton.

But a late letdown led to a crushing 21-17 loss for the defending-champion Eagles, who fell to 3-4 and watched their playoff chances take a hit.

“This one hurts because we freakin’ had it," Eagles tight end Zach Ertz said. "In terms of gut-wrenching [losses], this if freakin’ top two, for sure, top three. That’s the only way to put it.”

The killer, game-swinging play was delivered by a familiar face. With the Panthers facing a fourth-and-10 from their own 31 yard line with 2:06 remaining, Torrey Smith -- a member of the 2017 Super Bowl-champion Eagles who signed with Carolina in free agency -- took a pass from Newton and turned up field for a 35-yard gain, leading to a 1-yard touchdown from Newton to Greg Olsen that put the visitors ahead.

Alshon Jeffery drew a pass interference that set the Eagles up with a chance to score late, but Carson Wentz gave up a strip sack on fourth down to seal the win for the Panthers.

The loss is a blow to an Eagles team that seemed to be getting its Super Bowl swagger back. The Eagles rolled over the New York Giants on Thursday night in Week 6 and appeared to be on their way to a dominant win Sunday, playing with the same fun-loving, celebrating style that defined their 2017 run. Then the wheels came off.

They can certainly recover. They entered a half-game back of the Washington Redskins, and the NFC East race figures to be tight throughout. But they’re going to have to regroup fast before Sunday’s London game against the Jacksonville Jaguars before they play the Dallas Cowboys and New Orleans Saints over the next three weeks.

There is little give in their schedule, and they just made things a lot tougher on themselves by letting this one get away.

“We're going to find out what we're made of now, going forward," Wentz said "I feel like we said that two weeks ago; saying it again. We're at make or break time almost, so to speak; but it's hard to say exactly what it's gonna take."