Manning lost a fumble to concede a safety, threw an interception and was sacked four times on his return to the Lucas Oil Stadium to face a team he spent 14 years with as the Colts ended the Broncos' 17-match regular season winning streak with a 39-33 victory.
The 37-year-old insists that there were positives to take from the match, but admits that his side would need to improve if they were to keep up their strong start to the season.
"This is a game we need to learn from. We, I guess, had four turnovers and still somehow had a chance to win that game. I would have liked to have seen it go to a two-point game down there toward the end and see what would have happened, but it never quite got to that point," Manning told The AP.
"You can go back to different parts of the game and we got behind, mistakes there, but we still had a chance there at the end. We certainly have to improve from this game because we weren't as sharp execution-wise as we'd like to be.
"Hopefully we'll have a chance to play these guys again because that would mean we made the playoffs. I think if there is a next time it may be a little bit easier just because it was somewhat of an emotional week and it can be a little bit draining, I will say that."
The Broncos now sit second in the AFC West behind the NFL's only remaining unbeaten team the Kansas City Chiefs.