Early in the game, the Chiefs' offense showed everyone once again why they're the talk of the NFL, and then the 49ers came back and made a little run in the second half, but the Chiefs' defense stepped up and made enough plays to keep their undefeated record intact.

Here are 10 observations from 49ers-Chiefs on Sunday:

1. The atmosphere was what you'd expect

It was the home opener, and it absolutely felt like it. 

Chiefs' head coach Andy Reid mentioned it during his postgame presser and multiple players talked about it in the locker room after the game—that Chiefs' fans brought it on Sunday. 

And from the moment second-year quarterback Patrick Mahomes was announced during pregame introductions all the way up until the end of the first half, there was never a lull in the action for those thousands of members of Chiefs Kingdom in attendance. 

The crowd showed up to witness what the fans of the Chargers and Steelers already had to endure—at least from their perspective, and the show, particularly early, didn't disappoint one bit.

2. The Chiefs started quickly, again

The game couldn't have gotten off to a better start for the Chiefs, which had the defense take the field first—forcing a quick three-and-out by the 49ers' offense. 

It began with an incomplete pass from quarterback Jimmy Garoppolo, then a rush that resulted in a loss of two yards by the blazing-fast Marquise Goodwin after cornerback Steve Nelson came up to make a big tackle on the outside, and then on third-and-12, Garoppolo found tight end George Kittle for a gain of only seven yards. 

At that point, the 49ers then showed everyone that they wanted no part of punting the ball to Tyreek Hill, so they instead kicked the ball out of bounds, which meant they only netted 33 yards on the punt. The Chiefs began their first offensive drive at their own 43-yard line.

Then, it took just 11 plays and 57 yards before they were in the end zone, which came courtesy of a Kareem Hunt 1-yard touchdown run, which was his first of the season and one of his two on the day.

The Chiefs went on to score on each of their first five offensive drives, which gave them a 35-10 lead at halftime. 

They are still currently on pace to break the NFL's all-time scoring record, which is held by the Denver Broncos, who scored 606 points back in 2013.

3. The Chiefs' playmakers were making some moves in the open field

Both Hunt and Hill showed some nice open-field ability on that first offensive drive—juking 49ers' defenders and breaking tackles en route to that early lead. 

The key play on the Chiefs' first offensive drive may have been the third-and-15 pass to running back Spencer Ware, who raced through a couple of would-be tacklers before he was brought down just inches from a first down. 

Sitting at the 49ers' 19-yard line, Reid decided to go for it on fourth-and-1, running a speed option with Mahomes and Hunt out to the tight. Mahomes kept it for a gain of two yards to extend the drive. 

On the very next play, Mahomes hit fullback Anthony Sherman on a screen that resulted in a gain of 16 yards as he was eventually brought down just inches from the goal line. Sherman fought through multiple tacklers and ran hard enough to get most of the fans in attendance on their feet. 

It was the kind of physical display of running that has come to define Sherman's game over the past few years, and it was appreciated.

After the game in the locker room, Sherman joked that he went down on purpose just to make sure that Hunt could get his first touchdown carry of the year.

4. Chiefs' second touchdown drive was a textbook display of Andy Reid's genius

If you're looking for a drive or a set of plays on Sunday that illustrates Andy Reid's abilities as a play-caller and play designer, the Chiefs' second offensive drive demonstrated a couple of plays that you'd probably enjoy. 

One particular play that went to tight end Travis Kelce looked eerily similar to several other plays we've seen over the past couple of seasons now. 

Hill goes in motion, stops in the backfield and turns back to run the other way behind Mahomes as the ball is snapped. They've run multiple variations of this play, and this one resulted in what could have been a screen play to any number of people, but it found its way to Kelce, who took it up the field for a gain of 17 yards. 

Kelce finished the game with eight catches for 114 yards—the second-straight game he's had at least 100 yards receiving. 

Just four plays later after a key penalty was called in the end zone on the 49ers on third-and-16, which extended the drive and once again showed that Mahomes will always look deep first, Hunt would once again take it in from 1-yard out for his second touchdown in as many drives.

Overall, the Chiefs' play-calling early in the game just looked like Reid was showing off, particularly with the screen game and the window dressing that went into Kelce's reception, but it's also another variation that teams will have to try and prepare for, without even knowing all of the other tricks that could take place on that play concept, or a number of others ran on Sunday as well. 

Furthermore, the screen game was a big part of the Chiefs' offense early on Sunday, and that wasn't really a surprise, it was discussed during the week that the 49ers' run more Cover 3 looks than any other team in the league, and that leaves the flats (and seams between the hash and numbers) as the vulnerable spots against that coverage. 

The Chiefs had success there on Sunday.

5. Patrick Mahomes' first touchdown pass at Arrowhead was a memorable one

After the 49ers answered back with a touchdown of their own, which brought the score to 14-7 early in the second quarter, the Chiefs next drive wouldn't take long. 

Mahomes completed consecutive passes to tight end Travis Kelce, which went for 25 yards, and then to Hill, which went for 42 yards deep across the middle as Hill went up and made a nice catch in traffic, and then they were facing a third-and-goal from the 4-yard line. 

After scrambling around for a while—initially leaving the pocket to the left before he had to about face and come all the way back to the right, which had him run a total of 38 yards in all and saw him at one point all the way back to the 25-yard line, Mahomes eventually saw Conley running across the back of the end zone and fired a dart to him for the touchdown.

It was shades of his time at Texas Tech—some threw out that it was Brett Favre-esque, some mentioned Fran Tarkenton, and Reid laughingly said after the game that he "taught him that," but however it's ultimately described by those who saw it, the play won't be forgotten.

It was the perfect way for Mahomes' first touchdown pass at Arrowhead to happen.

6. Mahomes sets another NFL record with touchdowns to Demetrius Harris and Sammy Watkins

Last week against the Steelers, Mahomes finished with six touchdown passes, and combined with the four he had in Week 1 against the Chargers, was a new NFL record for the most touchdowns thrown in the first two games of a season for any player ever. 

So, he needed only two on Sunday to tie the record for most touchdowns thrown through three games, and he wanted to take any suspense out of that so he went ahead and did that in the first half. 

Following the touchdown pass to Conley, Mahomes had consecutive drives that ended with touchdown throws to tight end Demetrius Harris and then receiver Sammy Watkins, who had more than 100 yards last week against the Steelers but hadn't yet found the end zone. 

Mahomes is the talk of the NFL right now, and for good reason, but what's even more impressive than the fact that he finished Sunday's game 24 of 38 for 314 yards and three touchdowns, and that he's now thrown 13 touchdowns and has yet to throw an interception, is the fact that his 13 touchdowns have gone to nine different receivers.

Nine.

7. Dee Ford came up with a big sack on the 49ers' second offensive drive

One reason the Chiefs were able to start so quickly and get an early lead was that the defense had some stops early when the game was close. 

It's been a theme for the Chiefs' defense so far this year, that when the games have been close, they've actually done a good job of shutting down the opposing offense.

When games have been within seven points, the Chiefs have been the second-best defense in the league—allowing an average of just 2.71 yards per play. Once they've gotten a big lead, which means two or more possessions, those numbers change drastically, but when it has mattered, they've stepped up. 

And we saw that twice on Sunday. 

With the Chiefs holding a 7-0 lead early in the game, the 49ers' offense took the ball and drove a little ways down the field and were sitting within field goal range at the 37-yard line as they faced a third-and-11.

That's when outside linebacker Dee Ford, who was lined up over the 49ers' standout left tackle Joe Staley, anticipated the snap count, quickly got outside leverage on him and beat him around the edge—bringing Garoppolo down for a loss of seven yards on the play, which pushed them out of field goal range and they were forced to punt.

These plays shouldn't be forgotten.

During his postgame press conference, Reid said that Ford will have an MRI on Monday because of a groin injury suffered late in the game.

That sack was Ford's second of the year.

8. The other time the Chiefs' defense stepped up

With the Chiefs holding a 14-point lead with just seven minutes left in the game, the 49ers' offense drove down the field and were facing a first-and-goal from the Chiefs' 4-yard line. 

It was about to be a one possession game with plenty of time left in the game. 

That's when Chiefs' veteran defensive lineman Allen Bailey, who had a key sack in the second half of last week's game against the Steelers, stepped up big again as he drove the offensive lineman right back into Garoppolo's face and got his Hulk-like hand on the quarterbacks' jersey, and that's all it took.  

The sack resulted in a loss of eight yards. 

On the very next play, Justin Houston raced around the edge on the right side of the offensive line and picked up his second sack of the day—knocking the ball out of Garoppolo's hand in the process. 

While the 49ers' recovered the ball, the result was another loss of eight yards. 

They were just four yards away from a one-possession game, and two plays later, it was third-and-goal from the 20-yard line.

They were forced to kick a field goal after a third-down attempt netted just seven yards. 

When they had to, the defense stepped up once again—even if some of the box score numbers don't look pretty.

9. Ron Parker and Reggie Ragland led the team in tackles

Veteran safety Ron Parker and inside linebacker Reggie Ragland led the Chiefs defense with seven tackles each on Sunday. 

Parker recorded six solo tackles while Ragland had four solo tackles.

10. The offensive line closed it out

There's a certain pride that offensive linemen take when their team has a lead and they have an opportunity to run the ball for a couple of first downs in order to get into victory formation. 

It's when the defense knows you're running the ball, the fans know you're running the ball, people who don't even watch football know that's when you run the football, and you still are able to run the football and pick up yards. 

The Chiefs did that on Sunday—closing out the game with a couple of late, physical first-down runs by Hunt with the Chiefs holding an 11-point lead. 

The first "grind-it-out-run" came on a third-and-8 play with 3:29 left in the game, the 49ers' had just one timeout left, and Hunt took the ball right through the heart of the 49ers' defense for a gain of 10 yards. 

First down.

That's when the 49ers were forced to burn their last timeout, and then Hunt followed it up with runs of 6 yards, and then 1 yard before they reached the two-minute warning. 

Finally, on third-and-3 following the two-minute warning, Hunt ran for four yards, and that was it. 

Victory formation—with an exclamation point courteous of the guys up front.