KANSAS CITY, Mo. -- Saturday's final regular-season game began as many of the others did for the Kansas City Chiefs this season, with quarterback Patrick Mahomes leading the offense for a touchdown on its opening possession.

The game then continued into another familiar pattern, with the Chiefs struggling for points the rest of the way. They had to rely on their defense to come up with the winning touchdown, an 86-yard fumble return by linebacker Nick Bolton, during a 28-24 win over the Denver Broncos.

Starting and finishing fast is an emphasis for Mahomes and the Chiefs' offense in the playoffs, beginning with Sunday night's wild-card-round game against the Pittsburgh Steelers at Arrowhead Stadium (8:15 p.m. ET, NBC).

"It's just little things here and there," Mahomes said in explanation. "That's how it is in this league. We've been blessed enough that we've been able to execute at a high level these last few years, including pretty much the beginning half of this season, that we don't have to worry about them. But you're seeing that with the little things here and there on drives. They're stalling out, and that starts with me getting us into the right play and making the right throw to get the completion.

"You've seen it in every game pretty much that there's been times where we kind of stall out and we don't execute or I throw a ball and don't hit the right spot, or the receiver doesn't see it the same way I do, or penalties or turnovers."

The Chiefs couldn't have asked for a better opening-possession drive than the one they got in Denver. Mahomes completed passes to four different receivers as the Chiefs drove 91 yards in 17 plays and took almost eight minutes off the clock. They went 4-for-4 on third down, the drive ending on Mahomes' 3-yard touchdown pass to Travis Kelce.

The Chiefs led the NFL during the regular season with nine first-possession touchdowns. They were tied for the league lead in first-quarter scoring by averaging 7.65 points. They scored a first-quarter touchdown in their final 10 games, the third-longest streak within a season in NFL history.

In Denver, the Chiefs managed one more offensive touchdown and two field goals after their opening drive. During their 17 games, they were 20th in scoring from the second quarter on at 19.4 points per game.

As Mahomes indicated, the Chiefs have committed many untimely offensive penalties later in games that put them in long-yardage situations they haven't been able to overcome. For a stretch earlier in the season, the Chiefs were committing a lot of turnovers, but that hasn't been as much of a problem lately.

The Chiefs were also tied for ninth in the NFL in dropped passes during the regular season with 24.

"We've got to take care of those things," coach Andy Reid said. "It's not necessarily the adjustments that the other team is making. It's just that we've got to make sure we take care of our business. That's kind of where we're at right now, but we'll get that done. That's my responsibility and [offensive coordinator Eric Bieniemy's] responsibility to make sure we take care of that."

The Chiefs, like many NFL teams, script their first 15 offensive plays before the game, though they occasionally make adjustments depending on game situations. The goal is to give the opposing defense plenty to see and react to, but the Chiefs are executing their 15 plays better than any other team in the NFL.

"The thing that we want to do, obviously, is just diversify what we're doing, giving the defense a few different looks," Bieniemy said. "Other than that, we want to give our guys an opportunity to go out there and play fast. So, obviously, we've been scripting the first 15. I don't know it any other way since I've been in this coaching profession. I think it's something that gives our guys a unique opportunity to know what's expected, and also it gives them the ability to basically visualize and see it, and now they have that ability to make it happen when called upon."