When De'Anthony Thomas took a swing pass from Alex Smith 17 yards for a touchdown on the Kansas City Chiefs opening drive of the second half on Sunday there was reason for 49ers fans to be concerned. Up to that point in the game the Chiefs had scored on 3 of their first 5 offensive possessions and rolled up 228 yards of offense. So what happened?

After that Chiefs touchdown the 49ers offense, defense and special teams suffocated the Chiefs. The San Francisco defense limited Kansas City to 37 yards on 13 plays over their final 4 possessions, only 5 of those plays coming in the fourth quarter.

Let's take a look at a few plays that were key to the 49ers putting the Chiefs away.

- With just over one minute left in the third quarter and leading 17-16, the Chiefs faced a 3rd and 4 on the San Francisco 36 yard line. Alex Smith took the shotgun snap and rolled to his right. Demetrius Harris ran a drag route from left to right. Harris had a step on Michael Wilhoite, but Smith's pass was a little low and behind him resulting in a drop and giving the ball back to the 49ers.

- After Frank Gore was stuffed on the ensuing possession the 49ers faced 4th and 1 on their own 29 yard line. Jim Harbaugh threw caution to the wind and called his first fake punt since week 16 of 2012 in Foxboro. The result was a 3 yard run by personal protector Craig Dahl and the 49ers drive would continue.

- The two plays after the successful fake punt net the 49ers no yards so they face a 3rd and 10 on their own 32 yard line. The 49ers line up with three wide receivers and the Chiefs send a very well designed overload blitz to the left side of the 49ers offensive line. Carlos Hyde and Alex Boone do a nice job of picking up the blitz just enough to allow Colin Kaepernick time to get the ball out towards Brandon Lloyd who is matched up against Sean Smith in single coverage. Lloyd does a good job of locating the ball and going up for an incredible acrobatic catch for a 29 yard gain.

The 49ers drive the ball down to the Chiefs 9 yard line before having to settle for a Phil Dawson field goal to take a 19-17 lead.

- On the ensuing Chiefs possession they face 3rd and 1 on their own 32 yard line. Smith takes a 5 step drop and has Dwayne Bowe wide open on a quick out in the left flat. 49ers outside linebacker Ahmad Brooks does a good job of recognizing the play and gets into the throwing lane to knock the pass down and force a Chiefs punt.

- The 49ers then drive the ball into Chiefs territory before being forced to bring on Phil Dawson for what would have been a 54 yard field goal attempt. The Chiefs make a mistake with their substitutions and come to the line with 12 men. The penalty gives the 49ers a first down and allows them to bleed the clock down to only 2:12 remaining in the game after Phil Dawson hit his fifth field goal of the game for a 22-17 49ers lead.

- With the Chiefs now needing to score a touchdown they ask Smith to throw his deepest pass of the game, 23 yards, and he has tight end Anthony Fasano open down the right seam but he airmails the throw. The 49ers are sitting in a Cover 3 zone which allows Perrish Cox to be in position for the interception and put the game away.

In the end the 49ers won this game with a total team effort. They pounded the ball at the Chiefs on the ground, hit clutch throws, played strong defense and took advantage of a couple mistakes by their opponent. The same basic formula that has carried them to 38 regular season victories since 2011.