Richard Sherman knows what it's like to reach the top of the NFL mountain with his teammates. For this young San Francisco 49ers squad, that feeling is unknown. In fact, most of them have become accustomed to losing.

That isn't the case this season.

The 49ers are seeing all of their hard work over the past few seasons finally pay off. The team is 5-0 and tasting success for the first time under this regime — or the last few regimes. It always knew success would come. Now, it has to work just as hard to ensure that success isn't taken away.

The success of the 49ers defense has surprised many outside of the team's locker room. The unit set single-season NFL records last year. Unfortunately, they weren't marks worth bragging about. They were for the fewest interceptions (2) and fewest takeaways (7) in a single season.

It seems the 49ers' bolstered pass rush has helped this defense reach its potential — finally.

"They have been told they're not good," defensive coordinator Robert Saleh told reporters on Thursday. "They have been told that they shouldn't be here. They have been told that they should all be cut. We have all been told that we should be fired. So, don't forget what it's like to be on the other side of the fence, and don't think that just because you're being patted on the back that you are going to continue to have success.

"We got to this point because we've been working our butts off through adversity, through all the trials and tribulations that go with losing. Don't forget what it took to get here and don't forget what it's going to take to keep it.

"So, their mindsets are all in the right spot. They are absolutely grinding. They're focused, and they are excited to get out there on Sunday."

Outside of the locker room, the expectations surrounding the 2019 49ers are soaring. People are talking playoffs, division crowns, and maybe more.

Maybe, much more.

It comes with the 5-0 territory.

Inside the locker room, no one is focused on anything beyond Sunday. It's a one-game-at-a-time mentality.

"The results always come if you work hard," Sherman said on Thursday. "But being focused on the process is how you win championships; it's how you get over the hump. It's being focused on the task at hand, the process, and not the result, not the end goal.

"You sit there, and you focus on one game at a time. You make that a championship game that week. The next thing you know, you've played 19 championship games. And then you look up, and the season's over, and they have confetti coming down.

"Until then, you keep your eyes down. You stay focused on the prize, or you stay focused on getting better. [...] Any time you start sitting back and are like, 'Man, we're doing something special,' you get distracted, and that's when you get hit in the mouth."

Sherman believes the 49ers defense is comprised of unselfish players, and that's what a championship defense looks like.

"It's an essential part of (a) great defense, is being unselfish," Sherman added. "Selfish people can't play great defense because you're worried about (your)self. Great defense is worried about the whole. One person does not make a great defense in this league. It takes 11.

"It takes D-ends knowing at times, you're going to have to drop into coverage. At times, you're going to just have to take on double teams all day and night. It's going to take corners to know sometimes you're going to come up, and you're going to have to stop the run. [...] It takes linebackers being able to cover.

"It just takes so many people stepping out of their comfort zones, and out of their elements, and sacrificing for others."

No opponent is being overlooked. Not even the 1-5 Washington Redskins, whom the 49ers face on Sunday at FedExField, because as quickly has success has come, it can disappear even faster.