Denver Broncos quarterback Trevor Siemian (13) warms up prior to an NFL football game against the Carolina Panthers, Thursday, Sept. 8, 2016, in Denver. (AP Photo/Matt York)
ENGLEWOOD, Colo. (AP) Gary Kubiak didn't flinch when Trevor Siemian threw two interceptions in his first NFL start, and neither did the no-longer-unknown quarterback.
Siemian coolly led the Denver Broncos back from a late 10-point deficit for a 21-20 win over the Carolina Panthers in his first NFL start Thursday night.
He did so by engineering the kind of fourth-quarter comeback that made John Elway and Peyton Manning icons in this quarterback-crazed town.
Article continues below ...
''He's going to make mistakes. He's a young kid, but man, he played with a lot of poise,'' Kubiak said. ''He's going to watch film and he's going to get so much better.''
After speaking with Manning a day earlier – mostly about the retiree's latest funny commercials – Siemian became the first QB to start for a Super Bowl champion without ever having thrown a pass as a pro.
That changed on the game's first snap, when he zipped an 11-yarder to Demaryius Thomas, then threw four more passes before handing off to C.J. Anderson.
''It wasn't so much to build confidence as to show confidence,'' Kubiak said Friday, suggesting the only way a young QB gets better is for his coach to show faith in him.
Panthers coach Ron Rivera said Siemian ''was poised'' because Carolina's fierce front seven didn't pressure him enough.
''The thing that we didn't do and needed to do better, we should have shut the run down and forced the guy to win the game. We didn't,'' Rivera said. ''They ran the ball well and their offensive line did a nice job, and that's on us.''
Anderson helped keep that pressure off Siemian by running for 92 yards on 20 carries and catching four passes for 48 yards.
The Panthers led the league with 39 takeaways last year and they had two on Denver's first two drives, including an interception by linebacker Thomas Davis. Siemian's second pick came in the third quarter when cornerback Ben Benwilkere snared a high pass intended for Emmanuel Sanders at the Panthers 10.
''We missed a blitz pickup or else he throws a touchdown to Emmanuel,'' Anderson said.
Kubiak never sensed Siemian getting flustered, though.
''He really wasn't. Actually the second interception, it really wasn't his fault. Now, he has to throw the ball away (but) we should have picked it up,'' Kubiak said of the safety blitz that forced the turnover. ''He should have been able to step and throw. We didn't get that done. It's a team game. Obviously you have to protect the ball down there, but we sure as hell could have helped him.''
On the first play of the fourth quarter, Anderson took a screen pass 25 yards for the score that cut Carolina's lead to 17-14. Chris Harris Jr. intercepted Cam Newton two plays later and Anderson took it in from the 1.
Kubiak said he felt confident going in that Siemian wouldn't shrink in the magnitude of the moment.
''This kid is really exceptional,'' Kubiak said. ''I had a lot of confidence when I left the meeting (Wednesday) night.''
Kubiak said Siemian's teammates have to play better, but Siemian said it's those players who keep him calm.
''I'm just super confident in the group of guys we have offensively,'' he said. ''There are a lot of vets and a lot of great leadership in that group that I can lean on.''
They're rapidly realizing they can lean on him, too.
Notes: Kubiak said that while he was proud of his team's resiliency he wasn't happy about their recklessness: ''We made too many mistakes. I will not let up on them.'' Kubiak also disagreed with the costly illegal use of the hands penalty that Harris was flagged for on a fourth-and-21 incompletion to Kelvin Benjamin at the Panthers 29 that kept alive Carolina's final drive. ''I think the league got it wrong,'' Kubiak said. ''I thought it should have been called the other way.''
AP NFL website: www.pro32.ap.org and AP NFL Twitter feed: www.twitter.com/AP-NFL
Follow AP Pro Football Writer Arnie Melendrez Stapleton on Twitter: http://twitter.com/arniestapleton