The Jaguars' defense was truly special in 2017 before losing its way last season, which makes Sunday's season opener against the explosive Kansas City Chiefs a prime chance for redemption.

Jalen Ramsey, Calais Campbell, Myles Jack, Yannick Ngakoue, Josh Allen and every member of the Jaguars’ defense are now on the clock.

This is one of those defining moments for Todd Wash’s unit, as big a statement game in the 2019 season opener as it may have the entire season. It’s an opportunity to send a shiver-type message to the NFL about the Jaguars’ quest for redemption.

So if this defense wants the league to believe the Jaguars have their 2017 groove back, then a good start Sunday at TIAA Bank Field would be making league MVP Patrick Mahomes and all that Kansas City Chiefs’ weaponry look somewhat ordinary.

Jaguars coach Doug Marrone acknowledged Thursday the Chiefs’ offense, which put up an NFL-best 35.3 points per game last season, is as potent as any unit he’s seen in the last 20 years, including the “Greatest Show on Turf” of the St. Louis Rams and QB Kurt Warner.

“I’d put them up there with anybody,” Marrone said. “Yes, they're up there in that conversation and can easily be put up there with the best ones."

Wash admits there’s a hold-your-breath anxiety about dealing with Andy Reid’s offense, adding: “They’re fast at every position. If one guy [for the Jaguars] takes a play off, it’s probably going to be an explosive play. We’ve got to do everything we can to keep the ball in front of us. Hopefully, make them earn everything they can get.”

That said, it’s not like holding down KC’s offense is unfamiliar territory for the Jaguars. They did more than a respectable job in Week 5 last year against a pyrotechnic quarterback.

Of course, that part was easily overlooked in the Chiefs’ 30-14 victory because Blake Bortles threw four interceptions, putting his team in a 20-0 hole by halftime. That matchup -- by which time Mahomes had already thrown 14 touchdown passes and became an NFL headliner -- is remembered more for the start of the Jaguars’ seven-game tailspin that sent them plummeting to the AFC South cellar.

The narrative that got scant attention was it marked the only game in Mahomes’ brilliant season where he looked like a first-year starting quarterback.

Yes, he threw for 313 yards and tight end Travis Kelce had 100 receiving yards, but it was easily Mahomes’ worst performance in 19 career starts (including playoffs). He was held without a TD pass for the only time in the regular season. Cornerback A.J. Bouye and safety Tashaun Gipson each had interceptions, which contributed to Mahomes’ career-low 62.7 passer rating.

Mahomes had only two other games under 100 (89.5 vs. Denver and 91.5 vs. Baltimore). In two meetings with the Super Bowl champion New England Patriots, he had a combined rating of 113.2, throwing for 647 yards and seven TDs.

Sunday’s rematch becomes even more intriguing because not only do the Jaguars face KC in the presumably advantageous September heat, but the Jaguars’ defense is still fuming about how the 2018 disintegrated after a 3-1 start.

“We definitely felt real good about ourselves early last season, then lost our way,” Campbell said. “More guys are understanding you have to stay focused. You can’t lose you way. You have to do what’s required to win each and every day.”

Regardless of whether a broken-down offense was the root cause of an underachieving 5-11 record, this defense knows it added to the Jaguars’ implosion by letting selfishness and discord infiltrate the locker room.

NBC analyst Rodney Harrison, a 15-year NFL safety with the San Diego Chargers and New England Patriots, minced no words Wednesday when asked about what happened to the Jaguars’ defense.

“I looked at the Jacksonville defense last year and at times, they flat out quit,” said Harrison. “They didn’t play hard. They were yelling, they were pointing fingers. In order to have a great defense, which I’ve been on a No. 1 defense more than once, you can’t do that. You can’t point fingers. You have to stay as a unit. You can’t separate.

“It’s not offense versus defense. It’s not their fault versus our fault. You have to play as a team, as a unit. When I look at the Jacksonville defense, I think along the lines that they need to mature and they need to trust one another. They need to get back to playing physical.”

Harrison’s words weren’t much different from what several members of the Jaguars’ defense have already stated in the offseason. They were just more pointed and maybe cut deeper.

It’s an admonishment from an All-Pro player with a high national media profile, who is calling out the Jaguars by saying, in effect: “What are you going to do in 2019 to see it doesn’t happen again?”

Not to say this is the same Jaguars defense or KC offense, but most of the core players remain. Wash’s unit will have young safeties Ronnie Harrison and Jarrod Wilson replacing departed veterans Tashaun Gipson and Barry Church, so there may be matchup issues again trying to contain Kelce.

At weakside linebacker, rookie draft pick Quincy Williams must fill the void left by Telvin Smith, and with minimal preparation time due to a training camp injury.

But let’s not forget the Jaguars have arguably the best defensive line, bolstered by a versatile rookie pass-rusher in Allen, and cornerback tandem in the entire NFL. If that’s not a prescription to contain Mahomes, whose only significant missing piece from 2018 is running back Kareem Hunt, then what is?

With game-time temperatures expected to soar into the high 90s, this is as good a setup as any for the Jaguars to throw a Week 1 curveball. Not to mention it’s the highly-anticipated kickoff to the Nick Foles era.

So let’s see Mr. Armored Truck, Ramsey -- angling for the biggest contract extension in franchise history -- lock down explosive receiver Tyreek Hill a little better than he did last year (4 catches, 61 yards). How about a pass rush that puts Mahomes on the ground more than one time? Or a defense that holds the Chiefs to under 100 yards rushing? All those things may be mandatory for the Jaguars to prevail.

It’s a good sign the Jaguars’ defensive players took no consolation in keeping Mahomes from going off on them last year. In their mind, there’s only one path to redemption: winning.

Ngakoue didn’t even hesitate when asked what kind of message it’d send to the league if the Jaguars took down the Chiefs, saying: “S---, we’ll see them boys again in the AFC championship game. That’s all I got to say.”

Clearly, the Jaguars’ defense still fancies itself as an NFL standard-bearer. Well, there’s no better way to prove it than this: Let the youngest Superman quarterback the NFL has seen in years know that you’ve got the kryptonite to weaken him.

gfrenette@jacksonville.com: (904) 359-4540