Robert Turbin runs for 14 yards against the St. Louis Rams Sunday during Seattle’s 20-6 victory that clinched the NFC West championship. / Drew McKenzie, Sportspress Northwest

What every NFC team feared most came to pass Sunday: The Seahawks won the NFC West title with a tooth-pull, 20-6 victory over the St. Louis Rams and earned the conference’s No. 1 seed. With Green Bay’s 30-20 victory over Detroit, they sewed up home-field advantage throughout the playoffs. Following a bye next weekend, the Seahawks need two home wins to reach Super Bowl XLVIX.

Their opponent will be one of three teams: Carolina Panthers, Arizona Cardinals or Detroit Lions, that matchup to be determined on the basis of results next weekend during the wild-card round. The game will be at 5:15 p.m. Saturday, Jan. 10 (FOX).

After trailing 6-0 at halftime due to an offense that couldn’t make headway against the St. Louis defensive line, the Seahawks used three big defensive plays in the second half to break open the game and subdue the Rams.

An interception by defensive lineman Jordan Hill, the first of his NFL career, on a play in which Rams quarterback Shaun Hill tried to throw the ball away, paved the way for a Marshawn Lynch six-yard touchdown run. That gave the Seahawks a 13-6 lead.

A 49-yard interception return for a touchdown by Bruce Irvin, made possible by LB Bobby Wagner’s strip of TE Lance Kendricks after a catch, gave Seattle breathing room at 20-6.

Then, when the Rams threatened to put a dent in Seattle’s advantage late in the fourth quarter on a third-and-six from the Seattle one-yard line, FS Earl Thomas stripped RB Benny Cunningham near the goal line. The ball bounded through the end zone for a touchback, all but securing the Seahawks’ ninth division championship.

The Seahawks, who started the season 3-3, finished the regular campaign with a 12-4 record and an amazing flourish. They won their final six and nine of the last 10 to reach the postseason for the 10th time in the past 12 seasons.

Especially in the past six games, that run has been fueled mainly by Seattle’s defense, which Sunday held the Rams to 245 yards, only 42 on the ground. The Seahawks have held their past six opponents to 39 points, an average of 6.5. The margin of victory in those six: 134-39.

“We were three games out (after Week 7) and to come back like this just shows how good we are,” said linebacker Bobby Wagner. “In the second half, we just made plays. We turned it up. All we needed to do was get it to 7-6 and we would have been happy with that.

“Now, everybody has to come through Seattle and nobody wants to come through Seattle. The 12s have our backs.”

“We’ve just put ourselves in a great position to start the playoffs,” said LB O’Brien Schofield.

The Rams received field goals of 33 and 52 yards from Greg Zuerlein in the first half as Seattle’s offense struggled against a line that features four No. 1 draft picks. Russell Wilson had a 58.8 passer rating at intermission as the Seahawks failed to capitalize on two major opportunities.

Wilson overthrew Paul Richardson midway through the second quarter with the Seahawks driving in St. Louis territory, which resulted in an interception, and Lynch was stripped on Seattle’s subsequent possession, nixing another scoring chance. But the Seahawks asserted themselves offensively in the second half.

Wilson’s 32-yard completion to Richardson set up Steven Hauschka’s first field goal from 42 yards, and a 21-yard completion to TE Tony Moeaki set up Hauschka’s second, from 45. A 31-yard completion from Wilson to rookie Kevin Norwood provided Lynch the opportunity to run for a short touchdown, and then Seattle’s defense took over.

Wagner’s strip of Kendricks “changed the game,” said Carroll. “And that play by Earl Thomas near the goal line kept the momentum in our favor.

“We surely just witnessed how difficult the NFC West is in the last month. This is a tremendous accomplishment for us. We played a very tough game. We just had to keep battling and believe we could get it done.

“It’s a tremendous run of defense that we’ve watched. There was a time when we were 3-3, so to win the division is really a big deal because we get to play here throughout the playoffs.”

Notes

Tickets for the Jan. 10 game will go on sale for the first half of the Blue Pride season ticket waitlist at 10 a.m. Monday through an online account manager. Remaining tickets, two per person, will go on sale at 10 a.m. Tuesday at Ticketmaster.com or 800-745-3000. Season ticket holders renewed for playoff tickets at a 98 percent rate  . . . Irvin’s third-quarter interception return for a TD was his second of the season. He had a 35-yard INT TD against Oakland . . .  The Seahawks trailed 6-0 at halftime, marking the first time since Oct. 23, 2011 against Cleveland that they failed to score in the first half . . . Lynch, who rushed for 60 yards, has 17 touchdowns this season, a career high . . . In addition to winning nine of the past 10, the Seahawks have won 32 of  40 . . . .Wilson, who threw for 239 yards with one pick, is 36-12 as a starting quarterback in three seasons . . . LB K.J. Wright (hand) and DL Jordan Hill (sprained left knee) both left Sunday’s game in the second half . . . The Rams haven’t won in Seattle since Oct. 10, 2004, 33-27 in overtime.

SCORING SUMMARY

1st Qtr. (Rams 3-0): Greg Zuerlein 33 FG, 6:25. Drive: 11 plays, 35 yards in 5:38. Key Plays: Ricardo Lockette personal foul on punt return setting St. Louis up at 50-yard line; Jared Cook 12 pass from Shaun Hill.

2nd Qtr. (Rams 6-0): Zuerlein 52 FG, 4:19. Drive: 4 plays, 0 yards in 1:50. Key Play: Marshawn Lynch fumble after making first down to set up Rams at Seattle 34.

3rd Qtr. (Seahawks 6-3): Steven Hauschka 42 FG, 11:13. Drive: 8 plays, 56 yards in 3:47. Key Plays: Lynch 14 pass from Russell Wilson on 3rd and 14; Paul Richardson 32 pass from Wilson to St. Louis 26.

3rd Qtr. (Seahawks 6-6): Hauschka 45 field goal, 4:45. Drive: 8 plays, 42 yards in 4:27. Key Plays: Richardson 14 pass from Wilson on 3rd and 2; Tony Moeaki 21 pass from Wilson to Rams’ 27.

4th Qtr. (Seahawks 13-6): Lynch 9 run (Hauschka kick), 12:07. Drive: 6 plays, 54 yards in 2:44. Key Plays: Jordan Hill interception; Kevin Norwood 31 pass from Wilson to Rams 9-yard line.

4th Qtr. (Seahawks, 20-6): Bruce Irvin 49-yard interception return (Hauschka kick), 10:03. Drive: 5 plays, 28 yards in 2:13. Key Play: Wagner popped the ball loose from Lance Kendricks into Irvin’s arms.