Admit it.

When you first heard that the Dallas Cowboys had traded away a first-round pick to the Oakland Raiders for wide receiver Amari Cooper in late October, you laughed.

You said, or at least thought, “Yet another stupid move by Jerry Jones."

Cooper was a very good player for the Raiders. Had back-to-back 1,000-plus receiving yards in his first two seasons. Went to the Pro Bowl both years.

But his production dropped off last year (48 catches in 14 games, though he had a career-high seven TDs), and in six games with them this year before the trade, he had just 22 catches for 280 yards and one TD.

And here was Jones, the Cowboys’ impetuous owner/general manager, with yet another season slip-sliding away, giving up a first-round pick for the guy.

“That’s a steep price for anyone," said Eagles safety Malcolm Jenkins, whose own team would only need to spend a third-round pick a week later on wide receiver Golden Tate. “But it’s working for them."

Yes, it is. Six weeks after the trade, it is Jones who appears to be having the last laugh on everyone.

The Cowboys have won four of five games since acquiring Cooper, and take an NFC-East leading 7-5 record into Sunday’s critical battle against the 6-6 Eagles at AT&T Stadium.

Cooper has been a major reason for Dallas’s turnaround. In five games with the Cowboys, he has 30 catches for 425 yards and three touchdowns.

In seven games without Cooper, quarterback Dak Prescott had an 87.4 passer rating, a .621 completion percentage, and averaged just 6.9 yards per attempt.

In five games with him, Prescott has a 106.0 rating, a .728 completion percentage, and has averaged 8.0 yards per attempt.

“I think people kind of lost track of how good he really is," Eagles safety Corey Graham said. “His first couple of years in the league, he was unbelievable. Guys have a down year and you tend to forget about them. I think that’s what happened with him. But he’s really, really good."

The Eagles were reminded of that in their 27-20, Week 10 home loss to the Cowboys. Cooper, in just his second game with his new team, had six catches for 75 yards and five first downs.

He converted a second-and-8 and a third-and-7 on the Cowboys’ first scoring drive, and kick-started a second-quarter touchdown drive with a 15-yard reception.

In the Cowboys’ last two games -- a 31-23 win over the Redskins and a shocking 13-10 Thanksgiving Day victory over the Saints — Cooper was targeted 17 times and had 16 catches for 256 yards, 11 first downs and two touchdowns.

“He’s gaining a lot of confidence within the system," Eagles coach Doug Pederson said. “I think he and Dak, you can see [from watching the film] they’ve spent time during and after practice working on the timing of some routes.

“Amari has a better understanding of the offense and what they’re asking him to do. So he’s been able to play faster. You go back to the Saints game, it’s a close game and then, boom. There are two plays he makes and it’s a different story."

Cooper victimized the Saints’ best cornerback, Marshon Lattimore, on both of those boom plays. Beat him for a 14-yard completion on the Cowboys’ first touchdown drive late in the first quarter, then took a short pass from Prescott and spun around Lattimore for a 19-yard catch-and-run in the second quarter to help put the Cowboys up 13-0.

“They’re finding more ways to get it in his hands now," Graham said. “Obviously, he’s gotten more comfortable in the system, so he’s getting the ball more. He’s doing a good job and we need to find ways to combat that."

They’ll have to find those ways with a depleted secondary that is missing three of its five starters — safety Rodney McLeod (knee, out for the season) and cornerbacks Ronald Darby (knee, out for the season) and Jalen Mills (foot/toe, has missed the last four games).

Slot corner Sidney Jones, who missed the first game against the Cowboys, will move to one of the outside corners Sunday along with Rasul Douglas, who started against Dallas last month.

Defensive coordinator Jim Schwartz likely will use both Jenkins and Cre’Von LeBlanc in the slot in sub packages.

Before Cooper arrived, the Cowboys were impotent on third down, with a 31.9 percent conversion rate through the first seven games. Only Buffalo (29.5) and Arizona (22.8) were worse.

In the five games with Cooper, the Cowboys have converted 48.5 percent of their third-down opportunities, which is the third best rate in the league.

Prescott has targeted Cooper 13 times on third down. He’s caught 10 of those passes for 121 yards and eight first downs.

“He’s been exactly what we thought he was going to be," Cowboys coach Jason Garrett said this week. “He’s a very capable guy physically. He can run any route. Very smart. Plays a lot of different spots in our formations.

“He’s very comfortable just doing what we ask him to do. He’s been very productive. When we’ve thrown him the ball, good things have happened."

Cooper has benefited from the presence of running back Ezekiel Elliott, who is the NFL’s second-leading rusher with 1,149 yards. Because defenses have to worry so much about Elliott, it limits the extra attention they can give to Cooper.

“[Cooper] is in a situation where it’s not all on him," Jenkins said. “They’ve got Zeke back there. So, he’s able to win one-on-ones. The run helps him set up his routes and gives Dak open windows to throw through.

“They’re figuring out different ways to use him and get him the ball. Especially in crucial situations like third down. They can go to max-protect. He’s running some double moves. He’s a good route runner and they do a good job of getting him in situations where he can utilize that."

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