Football season is here! NFL week one is officially upon us, and that means fantasy football is back. Getting off to a 1-0 start is paramount, so you want to make sure you're starting the right pieces to succeed. When it comes to your starting D/ST, the opponent matters a lot, so you'll want to be wise about who you're locking into your lineup.
That may even mean you have to stream a better option as early as the first week if the defense you drafted is facing an elite offense on the other side. Which defenses should you feel comfortable starting in week one?
Defenses to start in week one

Cincinnati Bengals (vs NE)
This will be a common theme on these start lists throughout the season. If you start whoever is playing against the Patriots, you should find good results nearly every week. New England's offensive line is a disaster and they have zero reliable playmaking threats. With Drake Maye on the bench to start the season and the steadier Jacoby Brissett under center, the ceiling of the Pats offense is low. As for the Bengals, Lou Anarumo always fields a solid unit, and they should have no problems getting off to a strong start in this matchup.
Chicago Bears (vs TEN)
Chicago's defense was a different unit after the Montez Sweat trade last season, and even snuck the Bears back into fringe playoff contention. Chicago should be solid in the back seven, but the front outside of Sweat remains a question. That shouldn't be an issue against a Titans offense who tried to beef up their offensive line, but still is likely to struggle up front. The Tennessee wideouts should struggle against Chicago's talented secondary as well.
New England Patriots (@ CIN)
Cincinnati-New England has a chance to be a very low-scoring game. Bill Belichick is gone, but the Patriots still have the personnel and the scheme familiarity on their staff to field a very competitive unit in fantasy football, and it should keep them in this game against the Bengals. There are still offensive line questions in front of Joe Burrow, and Cincy's running game is suspect entering the season, so they'll have a hard time keeping this Pats pass rush honest. Look for New England to heat Burrow up early and often and make things tough for the Bengals, who may be without Ja'Marr Chase.
D/ST's to sit in week one

Pittsburgh Steelers (@ATL)
The Falcons' elite skill talent is finally free of Arthur Smith, and they're ready to be unleashed as a result. Their first victim is the Steelers, a unit that should be a rock solid option most weeks. However, week one is a bad spot for them. Atlanta has the requisite skill position talent to take advantage of Pittsburgh's cornerbacks in space and the offensive line to maintain a consistent running game. With Kirk Cousins under center, this Atlanta offense is dangerous and could have a big season opener.
Jacksonville Jaguars (@ MIA)
Nobody wants to play against Mike McDaniel, Tyreek Hill and the Dolphins after he's had weeks and weeks to prepare for a season opener. Unfortunately, that honor is bestowed upon the Jags in week one, and they just don't have the horses to keep up defensively. The Jags pass rush can be disruptive at times, but McDaniel is so adept at getting the ball out of Tua Tagovailoa's hands quickly that it probably won't matter. The Dolphins should be able to use their speedy playmakers to exploit Jacksonville's slower linebackers, and that smells trouble for Duval.
Kansas City Chiefs (vs BAL)
The Chiefs defense is going to be very good in 2024-25. However, it's tough to justify keeping a team that lost their best cornerback in L'Jarius Sneed off of this list as they prepare to play Lamar Jackson and Zay Flowers. Baltimore's offense will have a chance to really click this season without some of last season's growing pains in Todd Monken's first season as offensive coordinator. Kansas City's offense should put up points against just about everyone, and Baltimore will be forced to keep up. Jackson and company are more than good enough to do so against this Chiefs defense.
Looking Ahead
The defenses in the sit category, specifically the Chiefs and the Steelers, likely aren't worth just dumping right off the bat in your league. If you have an injured reserve stash (Nick Chubb, for example), you can use that extra spot to replace them, but if you have to let it ride then let it ride. However, keep an eye on teams that will be consistent streaming options such as Chicago and Cincinnati throughout the season. Picking the right defense can make a big difference in your matchup week in and week out. Happy fantasy football!