The Seahawks defense, including Clint McDonald (69), shut out the Saints for three quarters Saturday, and gave up only three points to San Francisco in week 2. / Drew Sellers, Sportspress Northwest

Rare is a sports season that goes to form. More rare is the heat between the San Francisco 49ers and Seattle Seahawks. The best teams in the NFC from the minute the previous season ended to this moment, throw down Sunday at the Clink to resolve their mutual contempt and move on to the NFL’s highest stakes.

Doesn’t get better.

Some Seahawks fans may have preferred to see Carolina in the NFC title game, but the Panthers were clearly the inferior team Sunday in their 23-10 home loss to the 49ers. The 49ers are in their third consecutive conference title game because they won their second consecutive playoff road game this season, remaining the premier NFC badass outfit until someone proves otherwise.

Or as Niners coach Jim Harbaugh, who drew an unsportsmanlike-conduct penalty Sunday for walking 15 yards onto the field to argue with a referee, shouted to his team in the post-game locker room celebration, recorded by Fox:

“Who can possibly be better than us?”

Team in unison: “Nobody!”

Your cue, Seahawks. Time to answer the question, “What’s your deal?”

The Seahawks have spoken well in the 49ers’ past two visits, winning by a combined 71-16, including 29-3 in the season’s second week. But that was then, before the return from injury of WR Michael Crabtree, and this is now, when the Seahawks beat a mistake-prone Saints team 23-15 Saturday despite only 103 yards of passing offense, a career low for QB Russell Wilson.

But in winning their fifth home playoff game in a row, the Seahawks accomplished a sly feat that doesn’t impress like big offensive numbers, but is equally important: They made few mistakes in crappy conditions. No turnovers, only six penalties, a reliance on defense and little deviation from their routines.

Saints coach Sean Payton is one who had a full appreciation of the deed.

“They’re patient,” he said. “They force you to be patient.”

The Saints wound up with 409 yards of offense, but found themselves down 16-0 entering the fourth quarter because they squandered four possessions — two with missed field goals and two with fourth-down failures that turned over the ball to Seattle. All told, a few dozen inches of difference, and the Saints go home while the Seahawks go on.

In week 2, the same Seahawks patience prevailed.

QB Russell Wilson missed on eight of his first nine passes, and the Seahawks led 5-0 at halftime — the first such halftime score in the NFL’s past 21 years. But urgency did not overtake the Seahawks in the second half. A steady 10-play, 80-yard drive opened the third quarter and was climaxed by a 14-yard touchdown run from Marshawn Lynch, followed on the next possession by a second 10/80 and another Lynch TD, this time a seven-yard pass.

Meanwhile, the defense held the 49ers to 207 yards of offense, just 100 from QB Colin Kaepernick, who threw three interceptions, was sacked three times and finished with a QB rating of 20.1.

But the 49ers won their final six regular-season games, including a 19-17 triumph over Seattle Dec. 8 in San Francisco, by an average of 11 points, then won a hard game in sub-zero Green Bay 23-20 to move out of the playoffs’ wild-card round round to Carolina.

Now they get to travel to their fourth road game in four weeks (Arizona before Green Bay and Charlotte) to the hardest place to win in the NFL.

But, oh, do they ache to do it. To shut up Richard Sherman, to shut up Pete Carroll, to shut up 68,000 Clinksters and to shut up all of the Northwest, the 49ers will bring a mad-on measured in megatons.

Seattle and the NFL have waited all season for this.

Game of the Year: The Trilogy.

There will be no sequel.