The Bears are yet to win at Soldier Field this season and were dominated by Joe Philbin's side as they cruised to a comfortable 27-14 victory, with quarterback Ryan Tannehill putting in an excellent performance in the match.
Trestman told reporters: "We didn't get the job done and that starts with me. We just couldn't get any continuity going with our plays.
"We should be playing a lot better at this point in the season."
The Bears are 3-4 in their season and travel to face the New England Patriots in their week eight clash.