"It damn sure doesn't seem like he just got here," quarterback Dak Prescott said. "Not at all, I mean at this point, after spending time with him, getting to know him better. Interesting dude. One of my favorite teammates."
Nobody has benefited more from Cooper's Oct. 22, 2018, arrival than Prescott, but Cooper has also benefited from the Oakland-to-Dallas change.
In his first 16 regular-season games with the Cowboys, he caught 91 passes for 1,346 yards and 11 touchdowns.
Since joining the Cowboys, Cooper is 10th in the NFL in receptions, fifth in yards and second in touchdown catches.
So far this season, he has caught 38 passes for 621 yards and five touchdowns. If not for a quadriceps bruise that limited him to one catch for 3 yards in three snaps against the New York Jets, Cooper, 25, would be on pace to threaten Cowboys records held by Michael Irvin and Dez Bryant (receptions, receiving yards and touchdowns).
In Sunday's 37-10 win against the Philadelphia Eagles, Cooper caught five passes for 106 yards, an impressive feat considering there were serious doubts he would be able to play because of the injury. But teammates say Cooper looked phenomenal in his one day of practice leading into the game.
"I didn't learn anything about him," coach Jason Garrett said after the victory. "It's the stuff I already knew and reaffirmed. He's a big-time playmaker. He's as tough as they come. He battled back from this thing and just played at a really high level. He's a difference-making player for us."
The Cowboys knew they needed that difference-maker after their 2018 Week 7 loss to the Washington Redskins. After past trades for wide receivers Joey Galloway (2000) and Roy Williams (2008) failed, they promised they would not make another major swing for a wideout again, yet Cowboys owner and general manager Jerry Jones and executive vice president Stephen Jones gave up a 2019 first-rounder anyway.
"Yeah, I think Stephen and Jerry knew something in that trade, you know?" tight end Jason Witten said.
The Joneses could not have envisioned the current success, but Cooper did.
"I wouldn't say it's been too far from what I expected," Cooper said. "I expected to come in here and be a playmaker and help this offense and help us win games. I think I've done some of that so far."
It took Prescott two practices -- tops -- to see Cooper was different.
"We're in the red zone doing fades, one-on-ones, and you try to coach him up, 'Hey, take your time, but when I throw it, you got to go get it,'" Prescott said. "I don't know what the hell release he did, but it looked like he walked off the ball, was looking at me and -- just bam -- he went to the back corner and the cornerback's sitting there like, 'Oh, s---, what happened?' It was one of our good corners. I don't want to call him out, but, yeah, at that moment I just realized his suddenness, and just the way he's so quick and just his movements are second to none."
In his first game with the Cowboys, Cooper caught a touchdown pass against the Tennessee Titans in Week 7. In his fourth game, he had 180 yards and two touchdowns, including a 90-yarder, against the Redskins.
In his sixth game, against the Eagles on Dec. 9, 2018, Cooper simply dominated. He had the sixth-best day a Cowboys receiver ever had with 217 yards and three touchdowns, including the winner in overtime, on 10 catches. And he did not have a reception in the first quarter of that game.
This season, in the Cowboys' Week 5 loss to the Green Bay Packers, Cooper had the fifth-best receiving day in team history with 226 yards on 10 catches and two touchdowns, becoming the first Dallas receiver with multiple 200-yard games.
"What's so impressive about Amari is his ability to play outside and play inside and run a variety of routes," Garrett said. "I've been around some elite receivers who are really good outside, some elite receivers who are really good inside. He has the ability to go to different spots in the formation and run the routes you need him run and win it. He's pretty darn good at it."
When Irvin had his 111-catch, 1,603-yard season in 1995, he and Troy Aikman had seven seasons of experience together. When Bryant had his 16-touchdown catch season in 2014, he and Tony Romo were in their fifth season together.
Cooper and Prescott have made up for the lack of time together by having their lockers next to each other. They sit side by side in team meetings. In July, they got together outside San Diego for workouts with some teammates.
"Dak and his timing, I mean, they're on the same page when they're expecting throws, what they're seeing in coverage," Witten said. "I think they've made what could be a tough transition -- he's only been here what, 16 games? -- they've made that seem very easy. Anybody that's been around this league for a short amount of time, you realize that's not always the case. It takes a lot of reps, a lot of practice to go through that. They've done it in a short time."
Romo couldn't get it done with Williams, but he immediately got it done with Bryant. Miles Austin had hours and hours of work with Romo, who helped make the receiver a two-time Pro Bowler (2009-2010). Prescott and Cooper have done what they have done from the beginning.
"I can't really explain it," Cooper said. "I got here and we were just able to click, and I think his game matches my game well, and sometimes it's just like that. It's like, I don't know if this is a good analogy or not, [but] it's like when you put certain foods together. Like if you put ketchup on a burger, it just tastes good together. That's how I would describe it."