CHICAGO (AP) Brock Osweiler refused to let a day go to waste while he waited for his chance - and watched one of the game's greatest quarterbacks.
He had a chance to learn from Peyton Manning and made the most of his opportunity when he finally got called on.
Osweiler threw for two touchdowns filling in for the injured Manning, and the Denver Broncos stopped Jeremy Langford on a 2-point conversion run in the final minute to beat the Chicago Bears 17-15.
Langford scored on a 2-yard run with 24 seconds left to cap a 65-yard drive. But the Broncos were ready for the run on the conversion attempt and stopped Langford to secure a narrow victory.
Osweiler completed 20 of 27 passes for 250 yards in the first start of his four-year career, while the five-time MVP stayed back in Denver because of injuries to his foot, ribs and shoulder. Osweiler got sacked five times, but he kept his poise against an aggressive defense. It all added up to a neat birthday for a backup who turned 25 on Sunday.
''I don't know if anybody believed me, but I really was telling the truth - I have not wasted a single day sitting behind Peyton,'' Osweiler said. ''I fully recognize that he might be the greatest quarterback to ever play, if not one of the greatest. I wasn't going to let one of those days go by where I didn't learn something. I've been very appreciative for my situation.''
Ronnie Hillman ran for 102 yards. The AFC West-leading Broncos (8-2) played turnover-free ball and got back to winning against former coach John Fox after dropping two in a row.
Osweiler threw a 48-yard touchdown to Demaryius Thomas on Denver's first possession of the game and a 10-yarder to Cody Latimer early in the fourth quarter to make it 17-9 after Chicago cut the lead to one.
''He does this all of the time in practice, in preseason,'' linebacker Von Miller said. ''I kind of came out here and expected it. What he did is what I expected him to do.''
The Bears (4-6) drove to the Denver 4 after Latimer's touchdown, only to have Jay Cutler's fourth-down pass to Langford in a crowd in the end zone get broken up.
Asked why he went for it rather than kick a field goal, Fox said: ''I think we hadn't made many trips down there, and when we had, we hadn't scored touchdowns. It had been kind of a field-goal game. At that point in the game, we felt that was going to be maybe our last opportunity so we were aggressive and came up short on fourth-and-4.''
Chicago also came up short in its bid to hit the .500 mark.
The Bears had won two in a row to jump into playoff contention in the NFC, something few would have expected this season. They are clearly making strides under Fox, who split with Denver in January after leading the Broncos to four first-place finishes in the division and a trip to the Super Bowl.
But Chicago had trouble reaching the end zone against the league's No. 1 defense, even though the Broncos were missing outside linebacker DeMarcus Ware (back). The Bears settled for three field goals by Robbie Gould before that late touchdown.
Jay Cutler threw for 265 yards in his first meaningful game against Denver since the trade to Chicago in 2009, even though the Bears were missing running back Matt Forte (knee) and receiver Alshon Jeffery (groin, shoulder). He had an interception and lost a fumble in the fourth quarter with the Bears on the Denver 33.
Cutler got hit by Von Miller as he was throwing and the ball popped up off a lineman before Denver's Malik Jackson cradled it.
The Broncos had a chance to add to a four-point lead midway through the third quarter after Danny Trevathan returned an interception to the Chicago 25, only to come away empty-handed.
Denver went for it on fourth-and-1 at the 2 rather than kick a field goal. That backfired when Hillman tripped on Osweiler's foot and got stopped for no gain.
''I've got to get my big feet out of the way,'' Osweiler said.
For at least one week, a 6-foot-8 quarterback with size 17s did a good job filling some big shoes.
NOTES: Bears RB Ka'Deem Carey exited in the third quarter with a concussion after a helmet-to-helmet hit from Denver's T.J. Ward. ... Broncos left guard Evan Mathis limped off the field with an ankle injury in the closing minutes of the game. ... Field judge Rick Patterson left in the fourth quarter with an injury. It was not clear how he was hurt.
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