SANTA CLARA, Calif. — Tommy Townsend trotted onto the field with fewer than four minutes left in the game Sunday, and for the first and only time, the Chiefs would use their punter to actually punt a football. Against the No. 1-ranked defense in the league. Well, formerly the No. 1-ranked defense in the league. Here are five observations from immediately after the game: 1. One mistake. Then: Game onPatrick Mahomes made one mistake. He threw an ugly pass to open this game. Bad ball placement. Bad decision. And, well, that was about it. Mahomes had more touchdowns in an earlier game this season….