After Week 13, the Tennessee Titans were 8-4 and tied with the Jacksonville Jaguars atop the AFC South. Three straight losses later, the Titans had dropped to 8-7 and their playoff hopes would come down to the regular-season finale against -- you guessed it, the Jags -- and along with it, coach Mike Mularkey's job. Rumors swirled that if Tennessee missed the postseason, Mularkey would be out of work.

But on Sunday, the Titans came to play. It wasn't pretty -- and it rarely has been this season -- but the defense limited Leonard Fournette to 69 yards and shut down Blake Bortles, who finished 15 of 34 for 158 yards with no touchdowns and two interceptions. Tennessee led 15-3 early in the fourth quarter and if not for a miscue between quarterback and running back, the score might have stayed that way. Instead, the Jags -- as they've done on a weekly basis -- leaned on their defense to keep them in the game.

In the end, it wasn't enough.

So for the first time in a month, the Titans got a win and for the first time since 2008, they're headed to the playoffs. And for at least another week, Mularkey gets to keep his job. But if he's hoping to hang around beyond that, Tennessee has a lot of work to do in the coming days.

How to Watch

Who: Titans vs. Chiefs
Where: Arrowhead Stadium, Kansas City, Missouri
When: Saturday, Jan. 6, 4:35 p.m. ET

It starts with Marcus Mariota

Mariota was the second overall pick in 2015 behind Jameis Winston and we're still waiting for him to play with the consistency of a franchise quarterback. Instead, he completed 62 percent of his passes this season (right in line with his career average) but set a career low in average yards per completion (7.1, down from 7.6 his first two seasons). He also set a career lows in touchdowns (13) and passer rating (79.3) and a career high in interceptions (15). He did rush for 312 yards and five touchdowns but his 5.2 yards per carry were also a career low. His best game of the season probably came in a Week 15 loss to the 49ers; Mariota finished 23 of 33 for 241 yards with two touchdowns, no turnovers and a passer rating of 110.8. 

But again, the issue is consistency; the week before, he barely completed half his passes and had a passer rating of 39.6 in a loss to the Cardinals. The week after the 49ers game, Mariota completed 56.4 percent of his throws and had a passer rating of 67.8 in a loss to the Rams.

On the season, Mariota ranks 19th in total value among all quarterbacks and is 20th in value per play, according to Football Outsiders' metrics. By comparison, he ranked 13th and 10th in those categories in 2016.

Which leads us to this: Mariota might be less than 100 percent.

This isn't an excuse but it would go a long way in explaining his struggles. In mid-December, longtime Tennessee beat writer Paul Kuharsky reported that Mariota's balky hamstring and surgically repaired lower right leg were still issues to the point that he could require offseason clean-up surgery on the lower leg that was fractured Dec. 24, 2016.

Unfortunately for the Titans, Mariota isn't the only problem; of the 12 playoff teams only two -- the Bills and Titans -- have allowed more points than they've scored, which means they're pretty lucky to have gone 9-7. This is confirmed by Football Outsiders' pythagorean wins formula, which is based solely on points scored and points allowed. Tennessee's expected wins using the formula: 7.4. By comparison, the Ravens, who also finished 9-7 but missed the playoffs after a late-game implosion against against the Bengals in Week 17, have an expected-wins total of 10.5 because they outscored opponents by 92 points.

The Titans' offense is replacement-level -- they rank 18th overall -- though the running game ranks eighth. Mariota is as responsible for that as he is for the 20th-ranked passing game. Derrick Henry and DeMarco Murray are 21st and 27th in value per play among all running backs. It's unclear if Murray will play Sunday while he recovers from a knee injury.

When Mariota does throw, he's usually looking for tight end Delanie Walker, who was targeted 111 times this season, 24 more than the nearest receiver. Walker caught 74 passes for 807 yards and three scores, followed by wideouts Eric Decker (54/563/1) and Rishard Matthews (53/795/4).

If the past four months have been a guide, the Titans will likely lean on their run game. It's what they do best and -- bonus -- it's what the Chiefs' defense doesn't do well at all. In fact, Kansas City's run D ranks dead last and is slightly better against the pass (No. 23). When Tennessee does throw it, Matthews should have opportunities; Kansas City ranks 31st against opponents' No. 1 receivers.

The Chiefs appear to be back on track

Sometimes stats can be misleading. Like some of the ones we cited above, particularly about the Chiefs' 30th-ranked defense. Because five weeks into the season, Kansas City was 5-0 and was the NFL's best team -- first in offense, 19th in defense. Then the wheels fell off; over the next two months, the Chiefs went 1-6 and somehow lost to the Giants and Jets. By that point, they had fallen to 10th overall (No. 6 in offense, No. 27 in defense).

Kansas City reeled off four straight wins to end the regular season, and in the process win the division and hold off the surging Los Angeles Chargers. And as they prepare to host the Titans, there are reasons for optimism. In that four-game winning streak Kansas City allowed 15, 13 and 13 points before giving up 24 against the Broncos on Sunday in a game in which most of the starters didn't play. They also generated 12 turnovers in that span after generating 14 turnovers in the previous 12 games. Then there's Alex Smith, whose struggles coincided with the team-wide issues -- the nadir came in losses to the Giants and Bills. In his four starts since, he is 3-1 with seven touchdowns, one interception and a passer rating north of 100. 

And unlike Mariota, Smith has shown that he can bring it on a weekly basis; he began the season with five straight games with a passer rating over 100 and it wasn't until Week 9 that he threw his first interception (he entered that game with 16 touchdowns).

And unlike the Titans' offense, the Chiefs have the luxury of diversity. It starts with Smith, who has quietly become one of the league's best quarterbacks, and it continues with rookie Kareem Hunt, who not only led the league in rushing with 1,327 yards (4.9 yards per carry) and eight touchdowns, but also hauled in 53 passes for 455 yards and three more scores.

For an idea of just how good Hunt has been, consider this: he ranks fifth overall in value per play, ahead of Le'Veon Bell, Mark Ingram and Ezekiel Elliott. And Hunt is Smith's third-favorite passing target after tight end Travis Kelce and speed merchant Tyreek Hill.

Kelce, with 83 receptions for 1,038 yards and eight touchdowns, is the league's second-best tight end behind some guy name Rob Gronkowski. And Hill, who had 75 catches for 1,183 yards and seven scores, is the NFL's No. 8 wide receiver, just behind Julio Jones.

So yeah, this is where things get difficult for the Titans. The good news is that they rank seventh overall in run defense. The bad news is that they're 24th against the pass and 21st overall. More bad news: In passing situations they're 24th against opponents' tight ends and dead last against opponents' running backs. And should Tennessee somehow find a way to bottle up both Kelce and Hunt, expect Albert Wilson to have a big day; the Titans are 28th against No. 2 receivers.

Who ya got?

The Chiefs are favored by 7.5 points and they're 10-6 against the spread this season and 8-5 against the spread as favorites. The Titans, meanwhile, are 8-7-1 against the spread and 2-1 against the spread as underdogs. 

Kansas City and Tennessee are teams going in different directions; the Chiefs are starting to resemble the team that started the year 5-0 while it's unclear if the Titans have emerged from their late-season funk that saw them drop three of their final four games. Not only that, but it's hard to imagine Tennessee having a game plan to slow Kansas City's high-powered offense, and Mariota and the Titans' offense haven't shown the consistency to keep them in games. Playing at Arrowhead Stadium, one of the NFL's toughest venues for road teams, further lessens Tennessee's chances of pulling off the upset.

Final score: Chiefs 28 Titans 17