It's hard to say if Brock is going to be good after seeing him in two tough spots. a road win vs Chi - Bears actually have a top 10 pass D (in terms of NY/A) and haven't allowed more than 23 points since their bye, so that win may have actually been higher quality than folks realized. Getting the W last night was great, but a lot of that was courtesy of the running game.
Now, Brock's presence certainly helps the running game (when compared to Manning's pistol/shotgun), but Brock certainly isn't the only QB capable of going under center. It's really hard to say if the teams improvement (and getting the W) is a function of Brocks positive play, or simply they don't have the negative of Manning.
Still, here are Brocks stats for the last 10 minutes Q4 and OT, against a top 10 passing D: 7-12 (58.3%), 121 yards, 1 TD, 0 int, QB rating of 120.5.
the man took the ball down by 2 TD's in the 4th quarter, against an undefeated defending SB champ on national TV, and was great. He led two TD drives (36 and 83 yards), and a FG drive (52 yards). Demaryius Thomas, by the way, had 5 missed targets during that stretch, which, IMO, makes Brocks performance that more impressive. If the normally reliable DT has even an average game, things would have been even better.