LAKE FOREST, Ill. (AP) — Khalil Mack sat out offseason workouts and the preseason, had just one week to learn a new system following a blockbuster trade, and still managed to dominate in his debut for the Chicago Bears.

The two-time All-Pro performed exactly as envisioned in a prime-time opener.

The Bears hope for more of that when they host Russell Wilson and the Seattle Seahawks on Monday night. They’d just like a different outcome.

Chicago blew a 20-point lead in the second half against Green Bay on Sunday night, with a hobbled Aaron Rodgers leading the Packers to a 24-23 victory that spoiled Matt Nagy’s coaching debut. But before that rally, Mack was the one stealing the spotlight.

“Obviously he’s stepped in very well,” defensive coordinator Vic Fangio said. “But I think everybody likes to overanalyze things — how much can you play a guy that’s just come in like that, no training camp, no nothing, hasn’t played since whenever his last game was last season? But I think with special guys, you throw that stuff out the window. He’s a special player. He did special things under special circumstances.”

Mack held out the entire offseason and preseason with Oakland while seeking a long-term contract extension rather than play under the final year of his rookie deal. The Raiders finally traded him two weeks ago. And the Bears gave Mack the richest deal ever for an NFL defensive player: a six-year, $141 million extension that guarantees $90 million.

Some long sessions getting up to speed with outside linebackers coach Brandon Staley followed.

“I’ve been ready for the grind, been waiting five months to feel the grind,” Mack said. “Yeah, we’ve definitely been doing that.”