The battle for Los Angeles is no longer just a marketing gimmick.

Neither the Rams nor the Chargers will fully stake their claim to local fans when they meet for the first time Sunday since the two organizations relocated to the city. But as perhaps the best matchup of Week 3, the game will serve as an opportunity for each team to seize the spotlight as a long-term threat.

It's fitting that the Chargers will have to travel, so to speak, to the Los Angeles Coliseum as the road team. The Rams not only beat them to the punch in getting settled in the city, but also in reconnecting with the local fan base and becoming a member of the league's top class of contenders. As in so many years past, the Chargers will have to rely on Philip Rivers to carry them through in the game.

The 36-year-old quarterback is off to a strong start in his 15th season, completing 73.1% of his passes for 680 yards with six touchdowns and an interception. And the Chargers' third-ranked offense has found a big-play streak with 11 completions of at least 20 yards.

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The Rams, however, bring the league's top-ranked defense that is also on a six-quarter shutout streak. But after the star-studded group feasted against the winless Raiders and Cardinals, Sunday's crosstown showdown should provide a better litmus test for the cohesion of the unit.

Despite the threat posed by the Rams, Rivers seems likely to maintain his daring ways. Allowing big plays to develop could be tricky, however, with the dominating defensive duo of Aaron Donald and Ndamukong Suh potentially creating havoc on the interior. And Rivers will also have to be wary of Marcus Peters, who has hauled in four of his 20 career interceptions off the gunslinger.

But the Chargers can try to neutralize the rush by continuing to make running backs Melvin Gordon and Austin Ekeler central to the passing attack. The two have accounted for 23 catches, 248 yards and three touchdown receptions so far this season, and they can put a strain on the Rams' linebackers.

Here are four other matchups that will define Week 3 in the NFL:

Saints WR Michael Thomas vs. Falcons CB Robert Alford

Julio Jones routinely commands the spotlight at wide receiver, but it's Thomas who has a record 28 catches through two weeks. Even if he doesn't maintain that pace, the third-year pass catcher could use the NFC South showdown to announce his arrival as one of the league's most pre-eminent offensive threats.

While Drew Brees has historically spread out his targets, Thomas has emerged as a go-to receiver and has more than a third of the offense's receptions and receiving yards. He also has risen to the challenge against Atlanta, recording at least 66 yards in each of his four games against the Falcons while hauling in three touchdowns.

Alford has also stepped up his performance this season, however, and he should have help elsewhere in the secondary. But Atlanta will also have to commit considerable resources to defending running back Alvin Kamara, who could break his slow start as a rusher this season against the league's 24th-ranked run defense.

Jaguars G Andrew Norwell vs. Titans DT Jurrell Casey

The Titans have won four of the last five matchups against their AFC South rivals, including both games last season. That fact wasn't lost on Casey, who said after a Week 17 win that the Jaguars couldn't rightfully be called the kings of the division and later added he was confident that quarterback Blake Bortles was "going to choke" with the game on the line.

Even coming off a signature 31-20 win over the Patriots in which Bortles enjoyed perhaps the best performance of his career (376 passing yards and four touchdowns), Jacksonville players say they're still motivated by the sting of recent losses to Tennessee. Norwell, who joined the Jaguars after an all-pro season with the Panthers, will get the critical assignment of handling Casey. He'll not only be counted on to protect Bortles, who has been sacked only once in two games, but also provide a push for Leonard Fournette after the second-year running back missed last week's game with a hamstring injury.

But Casey, who had the ninth multi-sack game of his career last week against the Texans, might not be the biggest concern for the Jaguars along the lines. Former undrafted free agent Josh Wells steps in for just his fourth career start at left tackle for Cam Robinson, who suffered a torn anterior cruciate ligament, and could have his hands full with savvy veteran pass rusher Brian Orakpo.

Seahawks OL Germain Ifedi vs. Cowboys defensive end Demarcus Lawrence

Ifedi entered this season widely viewed as a vulnerability for a suspect Seahawks offensive line. Yet just two games into the year, both the third-year lineman and Seattle's front might be at their breaking point.

Russell Wilson has been sacked a league-high 12 times through two games, and Ifedi has surrendered three of them. He also has been overpowered in the run game and ranks as Pro Football Focus' second-worst offensive tackle. While Wilson hasn't done his front any favors by holding onto the ball for extended periods, he hasn't gotten the protection or play-calling help he needs to succeed.

Dallas' defense, meanwhile, look to be in line for a feast. The Cowboys trail only the Bears with nine sacks on the season so far, and Lawrence is the kind of agile yet powerful edge rusher that has given Ifedi fits. Dallas also could go full bore on Wilson and Seattle's protection problems, as the team recorded five of its six sacks last week against the Giants on blitzes.

Buccaneers' offensive line vs. Steelers OLBs T.J. Watt and Bud Dupree

After getting torched by Patrick Mahomes and the Chiefs for six touchdowns, the Steelers opted to simplify their coverages to assist its out-of-sorts secondary. Even without those same breakdowns, however, Pittsburgh might only be able to repair its pass defense in time for Monday night's tilt by generating consistent pressure.

Watt had three sacks and a blocked field goal in the opener against the Browns, but he was a non-factor in the shootout against Kansas City. If he isn't able to create consistent havoc against right tackle Demar Dotson, who has been limited with a knee injury, Dupree will face an even heavier burden against left tackle Donovan Smith.

Even a healthy pass rush, however, might not be enough to slow the Buccaneers' top-ranked offense, as Ryan Fitzpatrick has the NFL's highest quarterback rating under pressure (153.3), according to Pro Football Focus. But given Tampa Bay's deep passing prowess with Mike Evans, DeSean Jackson and O.J. Howard, allowing Fitzpatrick extended time to operate is likely to prove lethal.

Follow Michael Middlehurst-Schwartz on Twitter @MikeMSchwartz.