THOUSAND OAKS, Calif. -- Todd Gurley remembers being a rookie in Seattle, near the end of the 2015 season, and scoring a touchdown.

"I kind of spiked the ball," Gurley said. "My teammate was like, 'Boy, what you doing? You better keep that ball. You know how many people score in Seattle? Nobody.'"

Gurley's Los Angeles Rams return to this hallowed place on Sunday, to face the division-rival Seattle Seahawks in a crucial late-season game that feels like a potential changing of the guard in the NFC West. The Rams (9-4) remain a game up on the Seahawks (8-5). They're the better team, trailing only the Philadelphia Eagles for the NFL lead in point differential, and they're also a lot healthier.

But none of that matters if they don't win.

The Rams lost to the Seahawks earlier this season, even though they outgained them by 134 yards. A victory in Week 15 would give the Rams a two-game lead with only two games left, essentially wrapping up a division title. A loss would sink the Rams to second place in the NFC West and probably place them on the fringes of a playoff spot, given the overall talent in the NFC South.

Gurley agreed that Sunday's game (kickoff is set for 1:05 p.m. PT on Fox) is as close to a must-win as one gets in the regular season.

"It's one of those games that you usually see other teams play in at the end of the year," Gurley said, "and we're in that situation this year. It'll be exciting."

The Seahawks have won the division three of the last four years and have gone to the playoffs in six straight seasons. But they seem an eternity removed from the Legion of Boom days of Gurley's rookie year, their home-field advantage dissipating in the process. The Seahawks went a combined 34-6 at home from 2012 to 2016, but have lost two of their last three at CenturyLink Field (though their last home game finished in a win over the first-place Eagles). Their defense ranks 10th in yards per play (5.09), while sitting eighth in rushing yards allowed per game (102.8) and 16th in passing yards allowed per game (226.3).

They're good, but aging, a slew of injuries keeping them from maintaining their place among the game's elite.

The Seahawks could be without Pro Bowl linebackers Bobby Wagner and K.J. Wright on Sunday, and they'll definitely be without cornerback Richard Sherman and safety Kam Chancellor, both of whom have been lost for the remainder of this season.

"God is good," Gurley said, playfully, when asked about facing a Seahawks defense without Sherman and Chancellor. "No, you hate to see guys like that go down. Two of the best DBs in the NFL. Just to see those guys still win, beat Philly -- that just shows you the type of team they are and they have become these last couple of years. No matter the situation, who's down, they have people to come in, step up. They just know how to win. That's just how they've been."

The Rams' biggest concerns come on defense, and they are singularly focused on one player.

"Russell Wilson, Russell Wilson, Russell Wilson," Rams defensive coordinator Wade Phillips said as he approached the podium on Thursday, referencing Seattle's Pro Bowl quarterback.

The Seahawks are burdened by a shaky offensive line and a non-existent running game, so they have relied on Wilson to make up basically their entire offense this season. Wilson has accounted for 32 of Seattle's 33 offensive touchdowns. He has thrown for 3,527 yards and run for 482 yards, enough to make him his team's leading rusher. His 17 fourth-quarter touchdowns are already an NFL record.

"You want to hate the other team, but he’s such a great guy," Phillips said of Wilson. "He really is. He does so many wonderful things, but we’ve got to try to beat him. He’s a tremendous player, tremendous individual, leader. He’s already done so many great things. It puts you at a big challenge. The guy makes plays on-schedule, off-schedule. He can throw it from the pocket; he can certainly run around and throw it and make big plays. He’s a handful."

But yet, so are the Rams.

Defense-adjusted Value Over Average -- or DVOA, a Football Outsiders metric that measures a team's success on a given play versus what would have been expected given several factors -- has the Rams as the NFL's best overall team at this point. They're scoring the second-most points per game while forcing the sixth-most turnovers, and they'll be boosted by the return of wide receiver Robert Woods and outside linebacker Connor Barwin on Sunday.

"Jalen Ramsey said it best: 'There's new big dogs in the league,'" Gurley said, referencing the Jacksonville Jaguars' dynamic cornerback. "Teams that haven't been doing good in the past, they've been able to step up. Just to see that, see what teams come through and be able to be where they're at today, means a lot for us."

The Rams have already locked up their first winning season in 14 years, but their turnaround isn't complete, and their standing as the new leaders of the NFC West isn't a reality, until they beat the Seahawks in Seattle.

Fitting.