Niners slip and slide their way to win and remain unbeaten.

The 49ers’ win over Washington Sunday in Maryland was every bit as ugly as the 9-0 scoreline indicated — at least when it came to conditions.

Relentless rain, a slip-and-slide field, and a nearempty stadium made for a dreary contest. But despite the miserable conditions and the throwback scoreline, the 49ers turned in a rather standard performance to move to 6-0 on the 2019 campaign.

They ran the ball with aplomb. Quarterback Jimmy Garoppolo made a couple of nice throws and nice plays with his feet. He also made a couple of questionable throws — one of which was intercepted. But more importantly than all of that, the Niners’ defense was outstanding yet again, posting their first shutout of the Kyle Shanahan era.

This has more-or-less been the Niners’ formula in all six of their wins this year. It’s solid, dependable, and has this team destined to reach the playoffs for the first time since 2013.

Yes, the rest of the NFL should be scared of this Niners’ team.

But the scariest thing about these 49ers is that they are nowhere near optimized — there’s plenty of room for this young team to improve as the season approaches its second half.

In fact, following a contest that will only be remembered for its quirkiness, I see six reasons to believe that the best is yet to come for San Francisco: 1. JIMMY GAROPPOLO CAN PLAY BETTER >> Garoppolo is now 14-2 as starting quarterback with 12 of those wins coming with the 49ers. You can’t argue with the record — only how much Garoppolo has to do with it.

From my perspective, the Niners’ quarterback has been average — at replacement level or better — this season. In past eras of the NFL, he’d be considered better than that, but in this pass-happy time, his play looks rather pedestrian.

Forgive me for my optimism, but I’d like to think that Garoppolo still has plenty of potential to tap — I believe he can play better than he has this season. He might have shown us a little late in the game against Washington, when he rallied from his interception to complete his final eight passes.

How much better?

That’s anyone’s guess, but I don’t think it’ll be debated when I say that his decision making can improve. Nine percent of Garoppolo’s passes Sunday were interceptable. That’s not just the weather Sunday — that’s how he’s operated since he arrived in San Francisco. On the season, Garoppolo is averaging two interceptable passes per game, which puts him in the same class as rookie quarterback Daniel Jones, Jameis Winston, and Jared Goff.

Surely Garoppolo can play better than those guys.

It’s clear that the Niners’ quarterback is becoming more and more comfortable with Kyle Shanahan’s offense and what his head coach is asking him to do — a symbiosis is forming there. But how effective could that duo be if Garoppolo was able to cut down on the bad decisions?

Maybe the gunslinging mentality is caked in — impossible to remove — and this is as good as it will get. (It’s still pretty good!) But if Garoppolo’s miscues are tied to offensive understanding and/or on-field reps, one would have to think that he’ll improve on those in the weeks to come.

Garoppolo has been good enough to take the 49ers to 6-0. That’s laudable.

But if he can make a jump in the final 10 games of the year, that might be awardable.

2. IMPACT PLAYERS ARE GOING TO RETURN FROM INJURY >> It’s easy to forget, because the backups have been playing so well, but the Niners are missing their top two offensive tackles — Joe Staley and Mike McGlinchey — a starting cornerback, and their linchpin fullback.

What happens when those guys are back to full health?

Of course, the NFL is a game of attrition — for every man who returns from injury, there’s typically another that goes to the shelf — but if the 49ers’ worst injuries are behind them, that bodes well for the remainder of the year.

As well as tight end Ross Dwelley has filled in as a makeshift fullback, having Kyle Juszczyk on the field allows Shanahan to deploy his full offense — the run and passing games will be markedly better when he returns to the lineup.

The return of Akhello Witherspoon — who was having a breakout start to the season before a foot injury fell him — will unquestionably bolster the Niners’ pass defense, which has been elite to date.

And as admirable as Justin Skule and Daniel Brunskill have been, they’re not Staley and McGlinchey, two of the best in the business.

Add in the possible injured reserve activations of receivers Trent Taylor and Jalen Hurd — two starter-quality offensive weapons — and the Niners could add enough talent that they could find another gear.

3. ROBBIE GOULD CAN RETURN TO HIS OLD FORM >> Longsnapper Kyle Nelson might not be injured, but he is set to return to the team this week after a 10-game performance-enhancing substances suspension.

Don’t scoff — this is a big deal for the Niners, who have used three different long snappers this season with none coming close to usurping Nelson.

The Niners are hoping that having a competent snapper on the ball in special teams situations might improve kicker Robbie Gould’s performance.

The Niners’ kicker might have been the only scorer in Sunday’s win, but he’s missed a kick in all but one game this year, missing seven of 19 total fieldgoal attempts. For a guy who doesn’t have a big leg and who signed a four-year contract in July, that’s simply not good enough.

I won’t pretend to know what’s wrong with Gould, but I presume Nelson’s return will help. And if Gould can get back to the form that earned him that four-year deal, the Niners will be good for at least three more points per game going forward. That stuff adds up.

4. THEY HAVE LOTS OF HOME GAMES COMING UP >> The schedule makers did the Niners no favors this year — they still have two games against Seattle as well as contests with the Panthers, Ravens, Packers and Saints this season.

But with six wins already under their belt, they only need four more to feel safe that they’ll be in the playoffs.

As fate would have it, they have four of their next five games at home.

In fact, six of the Niners’ final 10 games will be at Levi’s Stadium.

I don’t know if the Santa Clara stadium is a fortress, but the Niners sure prefer playing there to getting on a plane, and for three of their opponents (Carolina, Green Bay, Atlanta), there will be some body-clock challenges in play.