NASHVILLE, Tenn. – One of the hottest teams in the NFL, the Titans will be looking for their seventh win in eight games when they take on Arizona this Sunday.

This contest will mark the first of three straight games against NFC competition for the Titans, who have battled AFC foes in their last nine contests.

Here are five key questions for the Titans looking ahead:

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What milestone could Marcus Mariota reach Sunday? –** The Titans' quarterback could improve his record as a starter to 20-19, which would push him over .500 for the first time since the very first game of his NFL career.

That may not necessarily sound like much, but it's impressive considering how bad the Titans were during Mariota's first season (2015), when he went 3-9 as a rookie starter.

Since then, Mariota's guided the Titans to a 16-10 mark. His 16 wins as a starter over the last two seasons are tied with New Orleans' Drew Brees for ninth-best in the league during that stretch. Mariota has more wins as a starter over the last two seasons than Carolina's Cam Newton, Green Bay's Aaron Rodgers, Detroit's Matt Stafford and Baltimore's Joe Flacco among others.

It's not usually about big numbers for Mariota, but more about finding ways to win, evidenced by his four game-winning drives this year.

"Very efficient," Titans coach Mike Mularkey said about Mariota's winning performance against Houston, which saw Mariota record a turnover-free game.

"He ran the offense well enough to get us in position to score when we needed to. Took what the defense gave us. I just think he played efficiently for us."

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What's different about Titans running back Derrick Henry this season? –** Henry has shown both more explosiveness and elusiveness in 2017 while getting about three more carries per game.

In 2016, Henry posted only one run over 20 yards in 110 carries, and zero runs over 40 yards. This year, Henry has already produced five runs over 20 yards in his 125 carries, and two runs over 40 yards – a 72-yard touchdown run against Indy and Sunday's 75-yard touchdown run against Houston.

Henry had no problem outracing Texans defensive back Marcus Gilchrist in the open field during the TD run. That's because he reached a top speed of 21.64 miles per hour, per the NFL's Next Gen Stats, which ties Henry for the fourth-fastest ball-carrier speed of the season.

"I wasn't even looking at (Gilchrist)," Henry said. "I was looking at the end zone."

Henry has shown he can be slippery as well.

According to Pro Football Focus, Henry forced three missed tackles against the Texans. He's forced 15 since Week 9, second only to Saints running back Alvin Kamara (16) during that stretch.

Not too shabby, considering Henry stands 6-3 and weighs 247 pounds.

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What can tight end Luke Stocker do for the Titans? –** Asked if Stocker's game was similar to that of former Titans tight end Anthony Fasano, Mularkey said "I'd say very similar, yeah. Again, just having all that playing time under his belt."

That's good news for the Titans, as Fasano was one of the better blocking tight ends in the game during his two years here. The loss of Fasano was the only significant personnel change up front for the Titans from last season. Tennessee finished 2016 as the league's third-best rushing team (136.7 yards per game), but has slipped a bit to seventh this year (122.1 yards per game).

Titans offensive coordinator Terry Robiskie said a couple weeks ago that one of the challenges in the run game this season has been replacing a veteran like Fasano with rookie Jonnu Smith, who is still learning.

"I think that's a big difference and I'll always believe that when you replace an older veteran player with a young guy, the young guy will take a lot of lumps and bumps until he can figure out that part (blocking)," Robiskie said. "(Fasano) is gone and with Jonnu coming in, just like all the rest of the young guys, they're learning. It's a hell of a learning experience, especially for Jonnu. It's a big learning curve for him."

The 6-5, 253-pound Stocker is in his seventh season out of Tennessee, and has played in a system similar to that of the Titans in the past, so he should be a smooth fit in this offense.

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How will Rishard Matthews' return impact the Titans? –** Whether Matthews returns this week or later, he'll bring more big-chunk, downfield potential back to the passing attack.

Matthews is averaging 15.3 yards per catch, best among the team's wide receivers.

In addition, Matthews has eight catches of more than 20 yards this season and three touchdowns – both numbers tops among Titans wide receivers. Against Houston, the Titans posted only one catch of more than 20 yards – tight end Delanie Walker's 24-yard TD reception.

In the games Matthews has played this season, Mariota has averaged 232 passing yards. But with Matthews sidelined the last two weeks, Mariota has averaged just 167 passing yards per game.

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How does the Titans' defense match up with Arizona's offense? –** Over the previous seven weeks, the Titans have improved from 18th to third against the run by allowing an average of just 69 yards per game on the ground.

All seven of the Titans' opponents during that stretch have been held under 90 yards as a team.

That should give the Titans a decided advantage against the Cardinals' 31st-ranked rushing attack, which is averaging just 77 yards on the ground.

Arizona does have the NFL's 10th-best passing attack, thanks in large part to Larry Fitzgerald, who has 82 catches and five touchdowns. He'll be the latest in a string of good receivers the Titans have faced recently – a group that includes Cincinnati's A.J. Green, Indianapolis' T.Y. Hilton and Houston's DeAndre Hopkins.

"He's playing about as high (of) a level as you can right now," Mularkey said of Fitzgerald. "The quarterback trusts him and is throwing it to him, and he's catching all of them from what I saw this past game."

Cardinals quarterback Blaine Gabbert was sacked six times last week, which could bode ill for him against Tennessee. The Titans have recorded 15 sacks over the past three games, compared to 14 in the team's first nine contests.

-- Reach John Glennon at glennonsports@gmail.com and follow him on Twitter @glennonsports.