SANTA CLARA, Calif. -- Long before the San Francisco 49ers received the opening kick from the Dallas Cowboys on Sunday night, coach Kyle Shanahan already had an idea of what might be coming.

"I was real excited about us this week," Shanahan said. "I knew it was our biggest game so far this year, as far as nationally and just media wise and the hype. Sometimes you get worried your team might get too up for stuff. But just watching them all Wednesday, Thursday, Friday, they were so locked in all week. They didn't make too big of a deal of this game. They seemed so ready to go and kind of from a coaching perspective, we didn't feel like we had to do much all week, but just coach them, show the film, put in a game plan and our guys were ready."

That was a sentiment shared in the Niners locker room and confirmed just 3 minutes and 50 seconds into the game after the 49ers marched 75 yards on seven plays for a touchdown. Any sliver of doubt that the Niners' recent dominance against Dallas might end was quickly erased. Final score: 49ers 42, Cowboys 10.

"As soon as the offense went down on that first drive and scored, I was like 'we got them,'" sixth-year linebacker Fred Warner said. "The way they're operating right now is unbelievable. I've been a part of a lot of good teams since I've been here, but the way the offense is playing is unlike anything I've seen. That right there lets me know as long as the defense is doing our job, we're always going to have a chance."

Five weeks into the season, the 5-0 Niners look every bit a juggernaut that has more than just a chance at playing deep into the postseason and, perhaps, finally getting the franchise's long-awaited sixth Lombardi Trophy. They're one of two remaining unblemished teams (along with the Philadelphia Eagles), have tied a franchise record with 15 consecutive regular-season wins and own a plus-99 point differential, which is best in the league by a whopping 20 points.

San Francisco has scored 30-plus points in eight straight regular-season games, the fifth-longest streak in NFL history, and is the sixth team in league annals to score 30-plus points in each of its first five games of a season.

Since the Niners compiled many of those stats against struggling teams like the New York Giants (1-4) and Arizona Cardinals (1-4), it was fair to wonder how good they were prior to Sunday. Given that they've been to three of the past four NFC Championship Games, nobody doubted the 49ers; standing as one of the league's biggest threats, but the Cowboys (3-2) were supposed to be the first big test. A prime-time game broadcast to the whole country against one of their most hated rivals.

The Niners didn't just pass the test, they finished in about 40 minutes (out of 60) and got every question right, outgaining the Cowboys 421-197 in yards, posting 25 first downs to Dallas' eight and winning the turnover battle 4-1 on the way to their most lopsided victory ever over the Cowboys. The dominance was so thorough that Shanahan pulled most of his key starters late in the third quarter or early in the fourth.

"For sure, when you look at that game and look at other teams it's not even close," cornerback Deommodore Lenoir said. "I even try to give people the benefit of the doubt, but it's not close."

Next up for the Niners? They travel to play the well-rested Cleveland Browns (2-2) next week with the Browns coming off a bye, return to prime time the following week against the Minnesota Vikings (1-4) on "Monday Night Football", then host the improving Cincinnati Bengals (2-3) before their bye.

But make no mistake, the Niners will be favored in all those games and likely in every game they play until a much-anticipated showdown with the Eagles in Philadelphia on Dec. 3. Not that any 49er is looking past the Browns. The team's recent playoff runs have offered valuable reminders that the season is a marathon, not a sprint. When the Niners started 8-0 and went to the Super Bowl after the 2019 season, it was a new feeling. Only nine players and seven starters remain from that team, but the lessons are constantly brought up in the locker room.

That wisdom has been further instilled in the players that have been added since and hammered home by the team's veteran stars. Which is why, even after his team dominated one of its biggest rivals, left tackle Trent Williams was already harping on the (few) things that didn't go well against the Cowboys rather than the many that did.

"It's only Week 5, so the challenge is to keep this going and not peak out too early," Williams said. "We can be a lot better, we can. ... Our standard is good enough to beat pretty much any team on our schedule. As long as we're playing our standard, protecting the ball, re-focusing every play and not beating ourselves, I think it's going to be tough for guys to kind of handle what we present."