RENTON, Wash. — The showdown turned into a beatdown.

A game that figures to decide the NFC West title resulted in another celebrate-a-thon for the Seattle Seahawks as they turned in one big play after another in beating the Arizona Cardinals 35-6 on Sunday night.

In the process, they took a stranglehold on the No. 1 seed in the NFC playoffs, needing only to beat St. Louis at home this week (and for Detroit and Green Bay not to tie) to grab home-field advantage.

The fact that there is still one step left somewhat muted the celebration in the locker room afterward.

But on the sideline during the game, it was another story as players wildly cheered the many highlight-reel plays turned in by teammates, none more thrilling than Marshawn Lynch’s 79-yard touchdown run in the fourth quarter.

“Well, that’s about as much fun as you can have playing NFL football in the regular season,” coach Pete Carroll said after the Seahawks won their fifth in a row to improve to 11-4. “That was really an exciting night of football.”

Indeed it was as the Seattle offense gained 596 yards, setting a team record, while the defense held the Cardinals without a touchdown for the second time this season. That unit has allowed just 33 points in the last five games.

“We’re getting better every game,” safety Earl Thomas said in the kind of comment that has to frighten opponents.

One of the big storylines heading into the game was whether the Seahawks could handle an Arizona pass rush that sacked quarterback Russell Wilson seven times in Seattle — a game the Seahawks won 19-3.

Those worries grew when it became apparent late in the week that center Max Unger and left tackle Russell Okung would not play due to injuries.

But Seattle reconfigured its line (using second-year players Patrick Lewis at center and Alvin Bailey at left tackle) and helped protect Wilson well enough that he was sacked just once while throwing for a career-high 339 yards.

“The way the offensive line stepped up against one of the best defenses in the National Football League, I think that was the difference for us on offense,” Wilson said.

Seattle dominated statistically from the start, holding a 305-64 edge in yards at halftime.

But Seattle led just 14-6 heading into the final quarter due in part to three missed field goals from usually reliable kicker Steven Hauschka.

A 20-yard touchdown pass from Wilson to tight end Luke Willson early in the period started the floodgates, though. Then came Lynch’s run and a highlight-reel 5-yard touchdown scamper by Wilson, and the rout was on.

Seattle was just 6-4 when it hosted Arizona on Nov. 23, the Cardinals at that time standing 9-1 and the toast of the NFL.

But Seattle’s win that day began a turn in fortunes for each team. Arizona has gone 2-3 since then, while the Seahawks have won all five.

“To continue to play like this at this kind of level gives us real confidence,” Carroll said.

NOTES: LT Russell Okung was inactive after suffering a bruised lung against the San Francisco 49ers in Week 15. Indications are he will be able to return this week. … WR Jermaine Kearse suffered a hamstring injury while working in kickoff coverage in the first half and did not return. … CB Tharold Simon hurt his shoulder late in the game. … OG Keavon Milton was promoted from the practice squad on Saturday. Seattle waived TE RaShaun Allen. … C Max Unger may be able to return this week after missing the last five games with a high ankle sprain suffered at Kansas City on Nov. 16.

REPORT CARD VS. CARDINALS

–PASSING OFFENSE: A — A passing game that has been a slog for much of the season had one of its best days of the Pete Carroll era as Russell Wilson completed 20 of 31 passes for 339 yards, two touchdowns and no interceptions. The yards were the most of his career in a regular season game (he threw for 385 in a playoff loss to Atlanta in 2012). Injuries made for a fairly limited receiving corps. But tight end Luke Willson picked up the slack with three catches for 139 yards and two touchdowns, and wide receiver Doug Baldwin caught seven for 113 yards. Seattle averaged 10 yards per attempt, its most of the season, and Wilson didn’t throw a pick for the fifth time in six games. The pass blocking by an offensive line playing without starters Max Unger (center) and Russell Okung (left tackle) was vastly improved from the first game. Arizona had seven sacks the first time but just one Sunday.

–RUSHING OFFENSE: A — Lynch’s 79-yard run might have been enough for an A grade, but there was also a 55-yarder by Wilson that set an early tone and kept the Arizona defense off-balance, and Robert Turbin (38 yards on 10 carries) had some good moments early when Lynch sat out with a stomach issue. The run blocking was stellar as Seattle rushed for 267 yards on 34 carries. Getting the most done was the guard tandem of J.R. Sweezy and James Carpenter, whose run blocking remains their strength.

–PASS DEFENSE: A-minus — We’re picking nits here not to give them an A. But the Cardinals had a few open receivers early and couldn’t connect. The Seahawks also drew a pass interference penalty while defending Michael Floyd, and Richard Sherman gave up a 32-yard reception later in the game to Floyd. Sherman made amends with an interception and a 55-yard return to set up a touchdown and, for the most part, Seattle made Ryan Lindley look like the third-teamer he is as he had a passer rating of 47.2, completing just 18 of 44 passes for 216 yards. The pass rush continued its resurgence as well with four sacks, all by linemen.

–RUSH DEFENSE: A — If there’s an area of the defense that is better this year than last season it is the run defense, as was evidenced again Sunday night. Arizona didn’t have a run of longer than six yards and finished with just 29 yards on 15 attempts. Seattle knew Arizona would try to establish the run to take pressure off Lindley, having gone for 143 yards the previous week against the St. Louis Rams. But the Seahawks never let the Arizona running game get going. The same cast of characters came up big, notably middle linebacker Bobby Wagner and safety Kam Chancellor, whose ability to diagnose plays at the line and react quickly continues to stand out.

–SPECIAL TEAMS: C — There was one really glaring issue here Sunday night as kicker Steven Hauschka missed three field goals, which were all that kept the game close going into the fourth quarter. They weren’t necessarily gimmes, coming from 52, 50 and 47. The roof was closed and the conditions good and Hauschka has been reliable the last two seasons — he was 29 of 32 coming into the game. Probably just one of those nights. The return games were also something of an adventure — punt returner Bryan Walters fair-caught a punt at the 5. But the coverage was stellar as Arizona never began a drive outside its 21 on six kickoffs.

–COACHING: A — The Seahawks continue to look like a team peaking at the right time, with the coaches appearing to push all the right buttons each week to get the Seahawks through a stretch of games that looked particularly brutal when it began. Recall that Seattle fell to 6-4 on Nov. 16 after a loss at Kansas City, the first of six games against teams that had all won 10 or more games last season and were in the playoff hunt this year. Seattle, though, won the next five, all by 10 or more points and a combined 114-33. Seattle was in control of the Arizona game throughout, making moot the issue of a questionable call here or there. Pete Carroll again has Seattle looking like a Super Bowl winner, which is more than enough for an A right now.