The 49ers were without three of their top playmakers for much of the matchup, with running back Christian McCaffrey (Achilles) and wide receivers Brandon Aiyuk (knee) and Deebo Samuel (illness) all sidelined by the end of the day. Their final touchdown, a sneak by Purdy, came with under two minutes to play.

Brent Kelley, Mahomes’ basketball coach his senior year at Whitehouse (Texas) High, sees it in how Mahomes navigates “the chaos of every play” and his uncanny ability to make split-second decisions and move on to the next play even when something goes awry.

By the time the Kansas City Chiefs took the field Sunday at San Francisco, they already were the lone remaining unbeaten team in the NFL. They stayed that way with a 28-18 win.