SEATTLE – When running back Marshawn Lynch crossed the goal line to give the Seattle Seahawks their first lead early in the fourth quarter of Sunday’s game against the St. Louis Rams he skidded to a halt, spun and looked back, as if he were surprised to find no one in pursuit.

It’s been that kind of December for the Seahawks.

The Seahawks used two second-half interceptions to roll into the postseason by way of a 20-6 win over the Rams and secured the NFC’s top seed.

The defending champion Seahawks (12-4) won their sixth in a row, scored two touchdowns in a span of less than 2 1/2 minutes early in the fourth quarter to take a 20-6 lead in a game that helped secure a second consecutive NFC West title.

With the win, Seattle earned a first-round bye, at least one postseason home game and the right to host the NFC Championship Game if the Seahawks get that far.

“It means a lot,” linebacker Bobby Wagner said of the Seahawks clinching homefield advantage through the postseason. “Nobody wants to come up here and play.”

Lynch rushed for 60 yards and the go-ahead touchdown on a 9-yard run that came after defensive tackle Jordan Hill’s interception, putting Seattle ahead 13-6 with 12:07 remaining.

Just over two minutes later, Wagner broke up a pass that ended up in the arms of linebacker Bruce Irvin, who returned the interception 49 yards for another touchdown and a 20-6 lead.

The Rams marched down the field on their next possession but ended up turning the ball over again when Seattle safety Earl Thomas stripped the ball from running back Bennie Cunningham just in front of the goal line. The fumble rolled out of the side of the end zone, resulting in a touchback while giving the Seahawks possession.

“That was huge,” defensive end Cliff Avril said of the second-half turnovers. “Turnovers are big, and we strive to get as many as possible.”

St. Louis quarterback Shaun Hill completed 26 of 37 passes for 243 yards and two interceptions. Seattle’s Russell Wilson was 17 for 25 for 239 yards and an interception.

Seattle had to rally from a 6-0 halftime deficit, due in part to two turnovers and a failed fourth-down conversion.

The Rams (6-10) suffered a double-digit loss season for the first time since 2011, when St. Louis went 2-14.

“It’s certainly not where we wanted to be at the end of the year,” Hill said. “As I’ve said earlier, the difference between 6-10 and 10-6 is a couple of plays in four games out of 16.”

The Seahawks will get a bye before hosting Detroit, Carolina or Arizona in the divisional round of the playoffs. Seattle went 7-1 at home this season and has gone to the Super Bowl in each of its two seasons as the NFC’s top seed (2005 and 2013). The Seahawks have won their past seven home playoff games, dating back to a January 2005 loss to the Rams.

Seattle disproved the belief that Super Bowl champions were doomed to struggle the following year, and now the Seahawks are in position to become the first defending champ to repeat since the New England Patriots did it in 2003 and 2004.

“All you guys kept talking about: ‘You can’t do this. You can’t get back (to the postseason after winning a Super Bowl,’” Seahawks coach Pete Carroll said. “You can. We just did.”

Seattle looked in serious danger of repeating as NFC West champions when it opened the season with a 3-3 record and sat two games behind the Cardinals. But the season-ending knee injury to Arizona quarterback Carson Palmer opened the door for the Seahawks, which closed out on a six-game winning streak that saw opponents score just 39 points — an average of 6.5 per game.

“You always want to peak at the right time,” Wagner said. “Hopefully, we can keep it up.”

What the Rams said:

“I think we’re better than a 6-10 team, I personally do. I think we’re moving in the right direction.” –Coach Jeff Fisher

“Those guys made some spectacular plays in the second half, and we had some things go against us.” – QB Shaun Hill

“We beat them the first time, and we hung with them today. We know we are a better team than our record; we know that we are a better team than we display a lot of times.” –TE Jared Cook

What the Seahawks said:

“(Having homefield advantage) is big for us. I know I didn’t feel like flying anywhere. Being in Seattle and playing in front of these (fans) is big.” –DT Jordan Hill

“The real season just started. We’re back where we want to be, and we just have to keep going.” –LB Bruce Irvin

“Everyone counted us out, but we just stayed true to what we believed. It’s easy to win games when you’re playing for each other and you’re not trying to do anything special.” – DE Michael Bennett

What we learned about the Rams:

1. St. Louis would have had a heck of a season, had the Rams played everyone as tough as they played the Seahawks. For the second time in two meetings, St. Louis gave Seattle all it could handle. The Rams led 6-0 at halftime and were tied 6-6 early in the fourth quarter, until a pair of interceptions on back-to-back possessions turned the tide in Seattle’s favor. The Rams beat the Seahawks 28-26 in their last meeting.

2. The Rams are going to have to get creative if they’re going to solve their quarterback problems. The 6-10 record is better than that of seven other NFL teams, meaning St. Louis probably won’t get a shot at Marcus Mariota or Jameis Winston. Unless another draft prospect shoots up the charts during the scouting combine, the Rams might have to wait to see if someone like Jay Cutler or Robert Griffin III comes free over the next few months.

–LT Greg Robinson missed most of the first half after suffering a toe injury, but he returned to action after halftime. The No. 2 overall pick in the most recent NF draft ended up starting the final 11 games of the season, eventually taking over as the starting left tackle when Jake Long went down with a season-ending injury.

–DT Aaron Donald continues to make a case for defensive rookie of the year. He added his ninth sack of the season Sunday, giving him a league high among rookies. The No. 20 overall pick was quite an addition for a St. Louis team that was already rich along the defensive front.

–QB Shaun Hill wasn’t going to be the long-term answer at quarterback, but he could have helped his cause for a future roster spot with a better second half Sunday. He turned in one of his better statistical games of the season, completing 26 of 37 passes for 243 yards, but also had two costly interceptions – one of which was stripped from TE Lance Kendricks and returned for a touchdown.

What we learned about the Seahawks:

1. The defending champs are primed to do just that, although the New England Patriots might have something to say about it in the end. Getting back to the Super Bowl just got a whole lot easier, now that the Seahawks know they’ll be playing every other postseason game at home. Seattle went 7-1 at CenturyLink Field this season, has won its past seven playoff home games and has advanced to the Super Bowl each of the past two times the Seahawks had the NFC’s top seed.

2. The league’s best defense is playing even better than it did in 2013. Seattle has allowed just three touchdowns over its past six games while allowing 6.5 points per game. Sunday’s win saw the defense completely turn the tide with turnovers on three consecutive possessions, turning a 6-6 tie into a 20-6 blowout by the nine-minute mark of the fourth quarter. If Seattle’s defense can keep it up, it might be considered better than the 2013 unit. “We’ve got to wait until the end of the season,” LB Bobby Wagner said. “We’ll see how the Super Bowl turns out.”

–LT Russell Okung was back after missing last week’s game with a bruised lung. Okung didn’t have one of his best games but did enough to allow QB Russell Wilson to pass for 239 yards.

–WR Paul Richardson caught a career-high five passes on a day when WR Jermaine Kearse was sidelined by injury. Richardson, a rookie, led the Seahawks and seems to be finding his game at the right time.

–DT Jordan Hill has been a revelation over the second half of the season, but his status for the postseason is clouded by a minor knee injury. Hill made an amazing, diving interception on a pass that Rams QB Shaun Hill attempted to throw into the ground, and he was in on another sack. He came out of the game in the fourth quarter, due to an injured left knee, but said afterward that he feels “good.” Coach Pete Carroll said the extra week off should help Hill’s knee.

–RB Marshawn Lynch finished with 1,306 rushing yards, the second-highest total of his career, and a career-high 17 total touchdowns.