Looking back on three things discussed here before the San Francisco 49ers' 29-24 preseason victory Sunday at Denver:

1. Starting QBs. Peyton Manning played his best game of the preseason, completing 10 of 12 passes for 122 yards and two touchdowns. The 49ers, playing without top pass-rusher Aldon Smith, did not pressure Manning much. When they did, Manning showed he could deliver the ball downfield before withstanding a big hit that snapped his head back, putting to the test his surgically repaired neck.

Alex Smith's day for the 49ers wasn't quite as good. A short snap from center Jonathan Goodwin wound up on the ground, where the Broncos recovered it. Smith took a huge hit while delivering a short third-down pass for a conversion. Smith hung in, eventually finding Vernon Davis for a 44-yard touchdown. He completed 5 of 7 passes for 69 yards and did not throw an interception. Smith was pretty good. Manning was ... Manning.

2. Two-way threat. I'm guessing Demarcus Dobbs will emerge as the third tight end and part of the rotation on the defensive line, saving a roster spot for the 49ers. Konrad Reuland, also competing as the third tight end, did get into the game with the first-team offense, ahead of Dobbs. That doesn't necessarily tell us anything. Reuland had a 16-yard reception. But with the 49ers using defensive linemen as extra blockers, they appear in position to keep Dobbs as the third and final tight end on the 53-man roster.

3. Perrish's push. The 49ers' secondary struggled against Manning, but when backup Caleb Hanie came into the game, 49ers cornerback Perrish Cox stood out right away. Cox picked off a pass, his second interception of the preseason. Cox wasn't perfect as a tackler, but he appears to have created a role for himself within the 49ers' sub packages.