RENTON, Wash. — Earl Thomas says there is no room on the Seattle Seahawks’ bandwagon. If you weren’t on the ride already, Thomas says it’s too late.

Even if the Seahawks are suddenly one of the teams people are trying to latch onto as they surge toward the postseason.

“Don’t jump on the bandwagon now,” Thomas said Sunday night. “We have a chip on our shoulder and we play with it, and showed it.”

Seattle won its fourth straight game by beating NFC West-leading San Francisco 42-13 on Sunday night before a national TV audience.

That clinched at least a wild-card berth for the Seahawks sending Pete Carroll to the postseason for the second time in his three seasons in Seattle.

The win also kept Seattle’s slim hopes of winning the division alive and with it exactly what no one else in the NFC wants: being forced to make a trip to Seattle for the playoffs.

Seattle needs to beat St. Louis in the season finale and get an Arizona win at San Francisco for the Seahawks to win the division.

“Now we’re there with the opportunity to still win a division championship which would be huge for us and that obviously takes a lot of work somewhere else but we have to take care of our business first,” Carroll said on Monday.

Seattle (10-5) was already rolling toward the postseason with consecutive games reaching the 50-point mark, becoming the first team since 1950 to reach the half-century mark in back-to-back games. But those came against lesser competition in blowouts of Arizona and Buffalo.

The win over the 49ers legitimized what Seattle has been building. The Seahawks scored with ease on what was the top scoring defense in the NFL, led by rookie Russell Wilson’s four TD passes. And the win showed the Seahawks could be a tough opponent in the postseason.

Seattle doesn’t hide that it plays with a feeling of being overlooked. The Seahawks’ most notable moment this season was the “Fail Mary” against Green Bay where the Seahawks were on the receiving end of a blown call that eventually helped settle a labor dispute with the officials.

The blowout of the 49ers grabbed the kind of attention the Seahawks have wanted.

“The chip on the shoulder? That’s not something we just manufactured for the sake of getting fired up. The guys in this room feel that. Almost every one of these guys has their reasons. I feel like that myself. We just kind of share in that chip and we don’t even have to pass it around,” Carroll said.

“We all have one. That’s just kind of how it’s been. Just look, we’re up here in the Northwest and they like talking about us after they talk about everybody else. And that’s OK. That’s just the way it is. It doesn’t amount to much but sometimes it does fuel you a little to keep you going. It works for us so we’ll stay with it.”

The 42 points Seattle scored against San Francisco were the most allowed by the 49ers since 2009 and capped a remarkable stretch for Seattle.

The Seahawks have outscored their past three opponents 150-30. When David Akers kicked a 33-yard field goal in the second quarter, that snapped a streak of 100 straight points scored at home by Seattle — the final 21 against the New York Jets, all 58 against Arizona and the first 21 against the 49ers.

The Jacksonville Jaguars scored 94 points in eight home games this season. Seattle was the first team since the 1991 Washington Redskins to score at least 100 straight points at home.

Wilson will enter the finale needing two touchdown passes to become the NFL’s leader for TD throws by a rookie, passing Peyton Manning. In the past four weeks, Wilson has eight touchdowns passing and three rushing.

“We have a frontline, first-rate quarterback going out there in these games and you are seeing that,” Carroll said. “We trust him in his decision-making because he’s proven worthy of that.”

Seattle moved to the top of the league in scoring defense by solving the run-stopping woes that have hurt the team for the latter half of the season.

The problems started in Week 7 when the 49ers’ game plan surprised the Seahawks and they rushed for 175 yards as a team, including 131 by Frank Gore.

Seattle was giving up a league-worst 5.3 yards per carry since that loss to the 49ers, but returned to its base principles that served them well the first six weeks of the season.

The Seahawks never let Gore get started on Sunday. His longest run was 18 yards, but his other five carries gained just 10 yards. Even the running of Colin Kaepernick was corralled with the 49ers’ mobile QB held to 31 yards.

“We’ve been playing well for quite a while and I can feel it in the room and the guys can understand it and all,” Carroll said. “But that doesn’t mean anything unless we can do it again.”