GREEN BAY, Wis. – For the last four months, Derek Barnett has worked exhaustively on a counter pass rush move. The rookie defensive end's efforts paid off – at least as much as they can in the preseason – when he used an power stab move to sack Packers quarterback Brett Hundley.

Barnett's first sack in an Eagles uniform may have come against a second-unit tackle. But it was an early sign that he could apply pressure without his signature outside speed rush. And when Barnett decided to unleash the patented move that led to so many sacks at Tennessee, he notched another takedown of Hundley in the first half.

"I knew coming in that they like the quick game," Barnett said. "Our coaches told us to keep on pushing. Don't get down because the ball comes out quick. Just keep on grinding and you'll eventually get something."

It was a splendid debut for the Eagles' top draft pick, who played most of the first half and well into the second of the Packers' eventual 24-9 victory on Thursday. Barnett did most of his damage against backup Jason Spriggs, but his first series came against David Bakhtiari. And he hardly looked as if he was out of his element against the all-pro tackle.

"It was good to go against him," Barnett said of Bakhtiari. "But I go against [Jason Peters] and Lane [Johnson] in practice. They prepare me very well."

There have been times during training camp when Barnett has looked overwhelmed. But how many rookies skate through the grind of their first practices in the NFL? And Barnett hasn't used camp to polish what he excels at already. He has devoted much of his energy to adding a complementary rush to his arsenal.

He has tried spin and swim moves, bull and slap rushes. And on many occasions, he has looked like a relative novice in doing so. But if Barnett is to become the elite edge rusher the Eagles believe that he can become – even just a good one – he'll need to do more than just burn the corner.

Just ask Marcus Smith.

The Eagles don't necessarily need Barnett to dominate this season. Few rookie edge rushers – even those with a first-round pedigree – enter the league and have an immediate impact. But Barnett will spell Vinny Curry on the right to start the season. After that, who knows how long before he can supplant the veteran, who had a disappointing 2016?

Rookies have increasingly been called upon to contribute in their first seasons as the NFL has become younger. With second-round cornerback Sidney Jones possibly out for the season, the Eagles may not get the support they need from their draft class.

But a few, aside from Barnett, flashed enough against the Packers to suggest that they could be in the lineup as early as the opener against the Redskins on Sept. 10.

Mack Hollins made the second strongest impression. He was assisted, of course, by Carson Wentz, who slipped a would-be sack by Clay Matthews. But when the rookie receiver caught his quarterback's toss over the middle, he hurdled away from one defender and stiff-armed another on the way to a 38-yard touchdown.

Hollins' catch-and-rumble called for more passes to the fourth-round draft pick, but it took the check-downing Matt McGloin two quarters before he found the receiver again. But the quarterback was rewarded when he did. Hollins broke another tackle and scooted for a first down.

Donnel Pumphrey had a shaky start. He fielded his first punt when he should have fair-caught it, and he muffed his second only to pounce on the loose ball to avoid a turnover. But the running back had never field punts in college, and on his third try, he found light and motored ahead for yards.

Pumphrey was called upon often on offense. He once lined up in the slot with the first team. And he logged four carries and caught five passes. But the diminutive tailback netted only 17 total yards.

As for the other rookies, a review of the game film will eventually provide clearer answers. But third-round cornerback Rasul Douglas appeared to acquit himself well. At the least, he didn't get burned like his counterpart C.J. Smith, who bit on an inside move and gave up a 20-yard touchdown pass.

Fifth-round receiver Shelton Gibson, who has been plagued by drops in camp, had one pass slip through his hands. Fifth-round linebacker Nate Gerry made three tackles, but he also whiffed once in the open field. And sixth-round defensive tackle Elijah Qualls, who missed most of camp with a groin injury, muscled his way into a few run-stopping scrums.

But, ultimately, it was Barnett's night – as least among the rookies. Sacking quarterbacks is nothing new to the 21-year old. He had 33 in college. But an NFL first – even in an otherwise meaningless game – has meaning.

"It's fast, faster than college," Barnett said.

Barnett rushed from a three-point stance. He sprinted at Spriggs, but when they met, he used his hands to shove the 6-foot-6, 301-pound tackle aside. Spriggs might have appeared to be stuck in mud, but Barnett's closing speed was impressive as he pounced on Hundley.

"Once he got his legs under him, he played well, he played hard," coach Doug Peterson said. "It was exciting to see him around the quarterback.​"

A series later, he went back to his bread-and-butter move. Barnett's bend allowed him to cut the angle on Spriggs, who appeared to get away with a hold. But the rookie met Steven Means at the quarterback – it initially appeared as if Means took Hundley down – and picked up his second sack.

"I think what he did was what I wanted to do," Eagles defensive end Brandon Graham said, "get two sacks in the first game."

Barnett wasn't perfect, of course. Bakhtiari rag-dolled him to the turf once. And Spriggs mostly neutered his outside rush the rest of the way. But a defensive lineman needs only one sack for his performance to be deemed a success.

In his preseason debut, Barnett got two.