All throughout the week, Chiefs quarterback Alex Smith was asked about his return to San Francisco, where he was drafted No. 1 overall back in 2005 and spent the first eight years of his career.

Every time there was an opportunity, he was asked him about playing his former team. After the game, he was once again asked the question.

"It was different knowing a lot of the guys and even the scheme, having played against coach (Vic) Fangio," Smith said about preparing throughout the week. "It's tough. You're competitive. You want to win the game."

The Chiefs came out of the gate swinging on Sunday, scoring a touchdown on their opening drive in impressive fashion.

The 12-play, 76-yard drive took 8:37 off the clock and culminated with a two-yard touchdown pass to Travis Kelce, his third consecutive game with a touchdown reception.

The Chiefs converted three first downs on that first drive, including the touchdown pass to Kelce. Overall in the first half, the Chiefs converted 6 of 8 third downs.

Although that wasn't the case in the second half, when the Chiefs failed to convert any of their three third-down attempts.  This helped the 49ers hold onto the ball for 22:50 in the second half compared to just 7:10 for the Chiefs.

But Chiefs quarterback Alex Smith said that despite the loss, they're moving forward.

"I certainly think the last three to four weeks we are headed in the right direction," Smith explained.  "2-3 is not where we wanted to be headed into the bye week. Today is a tough loss but I think there are things you can take from it—a lot of room for improvement but things to continue to build on."

Smith finished the game 17 of 31 for 175 yards, two touchdowns and on the Chiefs final drive of the game, an interception.

With just over two minutes remaining and the Chiefs trailing 22-17, Smith and the Chiefs offense had the ball with a chance to drive the length of the field to get the win.

The drive stalled on the second play as a pass intended for tight end Anthony Fasano was intercepted deep down the field.  

Smith talked about that play after the game.

"We just had three verticals on that side, trying to hit Fasano up the seam," Smith said. "The ball got up a little bit. I didn't even see it. It's tough trying to make a play there at the end and move the chains. I thought I had it but the ball just got up on me a little bit."

There's no solace in defeat, but for the second time on the road this season, the Chiefs feel like they had one slip away and Sunday was no different.

"We all know we should have won the game but credit to the other team," outside linebacker Tamba Hali said. "We just have to put this one behind us and regroup as a unit and come back strong in two weeks and go get ourselves a win."

Fellow outside linebacker Justin Houston agreed.

"We made some crucial mistakes at the wrong time and they capitalized on that," Houston said in the locker room after the game. "So we have to learn from our mistakes and move forward. You can't let this game beat you twice.

"Now, we have to rest up and get our bodies right and get ready for San Diego."

Top Offensive Play

Rookie De'Anthony Thomas made his NFL debut on Sunday and despite limited touches, he made the most out of the ones he got.

At the start of the second half, Thomas took a swing pass from Smith 17 yards up the sideline to race in for the touchdown. The touchdown gave the Chiefs the lead at 17-13.

Smith talked about Thomas' debut on Sunday.

"Get him in space and he's got that kind of potential and you saw that today," Smith said.

The play was just a display of the speed and quickness that Thomas can bring to this offense, and his emergence into this offense moving forward will be something to watch.

Top Defensive Play(s)

The Chiefs were able to sack Kaepernick three times on Sunday, which gives them 15 on the season and ranks them fourth in the NFL.

Allen Bailey (1.5), Justin Houston (1) and Dontari Poe (.5) all got in on the action.

The defense was able to make some key stops in the second half and gave the Chiefs offense a chance late in the game to try and win it.

The defense didn't surrender a touchdown the second half, but the 49ers managed to get three field goals from veteran kicker Phil Dawson and that was enough.

Top Special Teams Play

All in all, the special teams play wasn't the highlight of the game for the Chiefs. The same probably can't be said for the 49ers, but the Chiefs did have one big play on special teams that was a positive.

Rookie De'Anthony Thomas' first career punt return in the regular season went for 28 yards and gave the Chiefs great field position early in the second half.

Thomas was able to break into the open field and set up the go-ahead touchdown for the Chiefs early in the second half (that touchdown was described above and was also Thomas).

Notes:

Jamaal Charles needs just 53 yards to pass RB Priest Holmes (6,070) for first place in franchise career rushing yards. He became just the third player in franchise history to record 6,000 or more career rushing yards.

Allen Bailey recorded 1.5 sacks (-9.0 yards) of QB Colin Kaepernick in Sunday's game. Bailey owns 2.5 sacks (-19.0 yards) for the 2014 season and has 4.5 sacks (-36.0 yards) for his career. His 1.5 sacks represent a single-game career-high for QB takedowns.

LB Justin Houston sacked QB Colin Kaepernick for a two-yard loss in the game, giving Houston 6.0 sacks (-14.0 yards) for the 2014 season. He ranks first in the NFL for most sacks in the 2014 after Sunday (with Washington's Ryan Kerrigan to play on Monday Night Football). Houston now owns 32.5 career sacks (-185.5 yards).* *

WR Junior Hemingway caught four passes for a single-game career-high 50 yards (12.5 avg.) in the game. His previous career-highs were five catches for 45 yards (9.0 avg.) in the 2013 season finale at San Diego on Dec. 29, 2013.