Five years later, Monachino arrived with the Bears this offseason as their new outside linebackers coach and reunited with Mack, who's now a five-year veteran and three-time All-Pro. He soon realized it wasn't just talent that has made Mack a superstar. That immense determination was still there.
Mack told Monachino he wants to be the greatest pass rusher to ever play the game.
"I hold myself to that standard every day," Mack said.
Whose greatness is Mack chasing?
"I mean, you got (Lawrence Taylor), you got Derrick Thomas," Mack said. "You got special, special guys that have played this position and that’s all you can do is kind of chase. You can’t really compare those guys, the best of the best.”
Mack, 27, was acquired by the Bears in a blockbuster trade with the Raiders last Sept. 1, then signed to the richest contract any defensive player has ever received, a six-year deal worth $141 million, including $90 million guaranteed.
Mack posted 12.5 sacks, six forced fumbles and a pick-six over 14 regular-season games in 2018, helping the Bears rank first in scoring defense takeaways. He earned Pro Bowl and All-Pro honors as a result.
But what has separated Mack in the minds of many at Halas Hall is the work ethic that he displays. Monachino has recognized that in their short time together.
"The first thing that strikes you is what a great pro he is," Monachino said. "His approach every day in the meeting room — whether it’s a small-group meeting, unit meeting or a team meeting — he’s locked in. He’s preparing every minute that he’s in the building.
"I’ve known how he is and I also know how important it is for him to be the best that ever played. I wouldn’t have expected anything other than what I’m seeing."
The presence of a talent like Mack working through every phase of the voluntary offseason program is notable. In New England, quarterback Tom Brady isn't with the Patriots for their work in OTAs. Out west in Los Angeles, four-time All-Pro defensive tackle Aaron Donald is skipping the Rams' optional team work. Many of the game's best simply prefer their own offseason regimen, and it's their right.
In Lake Forest, Mack is part of the Bears' near-perfect attendance for their offseason program, which began in early April and wraps up with mini-camp in June. Coach Matt Nagy sees a player of Mack's stature setting the tone for many of his younger teammates with a desire to be great.
Mack is making sure it spreads.
"Me and everybody else," Mack said. "We’re holding each other to a higher standard."