As if the San Francisco 49ers don't have enough dislike for the Seahawks, Seattle could clinch the NFC West with a win at San Francisco on Sunday.

As if the New Orleans Saints don't have enough headaches from being pounded by those Seahawks last weekend, they now face another staunch defense when the Carolina Panthers visit the Big Easy in an NFC South showdown.

Those are the highlights on one of the more intriguing weekends of NFL matchups. The regular season is into the fourth quarter.

"If this doesn't fire you up, if this doesn't fire up the fans, then what does?" 49ers coach Jim Harbaugh said. "I suppose Abraham Lincoln riding across the field with a frock and a top hat, riding a horse, waving an American flag. I doubt that would fire them up, if this game doesn't fire them up. The people that really love football would be fired up by this matchup."

There isn't a more physical rivalry in the league right now than 49ers-Seahawks. The two defenses don't let up, and the animosity is evident everywhere on the field — and on the sidelines, where Seahawks coach Pete Carroll and Harbaugh have a long-standing feud.

Makes for a juicy affair at Candlestick Park in a game far more critical to San Francisco's playoff prospects. Seattle clinched the NFL's first playoff berth with a rout of New Orleans on Monday.

Seattle has owned this series of late, outscoring the 49ers 71-16 in the past two meetings, both at home.

"Every game we play from here on out is important to where we go to get into the playoffs," 49ers linebacker Patrick Willis said. "Once we get in, then I feel like anything can happen."

The Seahawks don't doubt it. They have had a good view of the Niners' success the past two years since Harbaugh came aboard.

"They've been winning for a long time. That just makes it that much more of a challenge and difficult to get," Carroll said. "We're going for it with everything we've got this week."

The Saints have been on top of the NFC South all season, but were caught last week when they flopped in Seattle and the Panthers won their eighth straight game, beating Tampa Bay.

Saints quarterback Drew Brees bristled at the notion the Saints' last performance might have eroded their confidence.

"We've done things well for a very long time in a lot of different ways," Brees said. "One game does not set that back. One game does not change our mindset, our confidence level or our attitude in any way. ... We still know we're a great football team."

The Panthers' winning streak featured what was widely seen as a coming-of-age performance on a Monday night against New England a few weeks ago. Winning a night game in the Superdome, where the Saints are 6-0 this season, might be even more impressive.

"You don't really have to add much sugar to this one," Saints safety Malcolm Jenkins said.

Nor to the rematch in two weeks.

The Indianapolis Colts can clinch the AFC South with a win over the Cincinnati Bengals or a Tennessee Titans loss at Denver. Colts linebacker Robert Mathis leads the NFL with 15 1/2 sacks and needs one to surpass Dwight Freeney (16 in 2004) for the club record.

Cincinnati is 5-0 at home for the first time since 1988, when the Bengals won all eight regular-season home games and two playoff games before falling to San Francisco in the Super Bowl. Andy Dalton has thrown for 3,144 yards, joining Peyton Manning as the only players to throw for 3,000 yards in each of his first three seasons.

Week 14 began with the Jacksonville Jaguars beating the Houston Texans 27-20 on Thursday.

Jacksonville won at home for the first time since November 2012, while Houston extended its franchise-record losing streak to 11 games.

Also on Sunday, it's Detroit at Philadelphia, Kansas City at Washington, Cleveland at New England, St. Louis at Arizona, Miami at Pittsburgh, Minnesota at Baltimore, New York Giants at San Diego, Atlanta at Green Bay, Buffalo at Tampa Bay, and Oakland at New York Jets.

Dallas is at Chicago on Monday.