ENGLEWOOD, Colo. -- These are the times that certainly try defensive backs’ souls. And their confidence. And their preparation.

Covering elite receivers right now ain't for the faint of heart.

Antonio Brown had a career outing in 2015 against the Broncos. Gregory Shamus/Getty Images

“I’m not sure there’s ever been a time like this for guys back there," said former Denver Broncos cornerback Champ Bailey, a 12-time Pro Bowl selection in his decorated career. “You have to get everything so right on every play and you still might get a flag, or they still might let [the offenses] run a pick play, or the receivers just aren’t afraid of anything in the middle of the field anymore. They’re just running, make the catch and running some more. You have to hang in and tackle and just get it right."

The Broncos have certainly lived that life this season, given that they have already faced three of the most productive offenses in the league: the Kansas City Chiefs (twice), the Los Angeles Rams and Los Angeles Chargers. All three of those teams are just one long day after another for a secondary, and the Broncos get one more Sunday in the visiting Pittsburgh Steelers.

By the time Sunday is over, the Broncos will have faced the six players who entered Week 11 as the AFC’s top six in receiving yardage. The Chiefs, Rams and Steelers each have two players among the NFL’s top 15 in receiving yardage overall.

“You have to have perfect technique, perfect feet, play your technique every snap, you can’t mess up," Broncos cornerback Chris Harris Jr. said. “There isn’t room to mess up anymore, because you can’t really touch the guys too much and offenses are passing the ball all the time. So if you make a mistake, on the route, early with your hands, any time, it's hard to dig out from that before the ball is out [of the quarterback's hand]."

For the Steelers, that means a whole lot of Antonio Brown -- that’s a given -- with JuJu Smith-Schuster now far more than a plan B. It’s actually Smith-Schuster who leads the Steelers in catches (64) and receiving yards (866), which is just ahead of Brown’s 62 catches and 807 receiving yards.

But when Pittsburgh is in the scoring zone, Brown is still the primary choice for quarterback Ben Roethlisberger. Brown’s 11 touchdown catches -- he’s had at least one touchdown catch in nine of the Steelers’ 10 games -- is tied for the league lead.

“And the top guys, you always want to get their timing right away because a lot of those plays are rhythm plays -- the quarterback needs those guys to get to a certain spot right away," Bailey said. “So you have to put your hands on them if you can, but those fast guys who can go by you, that’s another mistake you can’t make. You can’t miss at the line of scrimmage, because you can’t be physical down the field now, so if you’re chasing the ball is going over your head. Sometimes you don't want to, but the best move is bend, but don't break, come up and make tackles and lock it down in the red zone when they don't have so much space to get separation."

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Sunday will be the fourth time the Broncos have faced Brown, one playoff meeting included; in two of the games, they have kept Brown out of the end zone and limited him to 74 or fewer yards. The other meeting, however, was a far different story.

In 2015, when Denver eventually finished at the top of the league’s rankings in virtually every significant category on defense on the way to a Super Bowl 50 win, Brown tortured the Broncos, and largely Harris, for 16 receptions, 189 yards and two touchdowns.

It enabled the Steelers to come back from a 27-10 deficit just before halftime to a 34-27 victory as Brown reeled in the winning touchdown.

“[Receivers and quarterbacks] are going to get you sometimes, that’s just how it is," Harris said. "You have to keep your head right and fight, man, you have to keep going out there and lock up on people. Because if they see you’re not ready to lock up, these quarterbacks right now will come right at you over and over."

After the trade of cornerback Aqib Talib to the Rams in the offseason, Denver has flip-flopped between stretches of quality play in the secondary and some struggles. Some NFL personnel executives say they’ve seen the Broncos’ best efforts when Bradley Roby, Talib’s replacement in the starting lineup, plays with more discipline.

Roby opened the week in the concussion protocol, which could affect how the Broncos align themselves against the Steelers. And last Sunday, the Chargers’ Philip Rivers targeted the Broncos’ safeties plenty on the way to 401 yards passing in a game Denver won with a field goal as time expired.

At one point in Sunday's third quarter, Rivers was 8-for-8 passing on third down for 176 yards.

“[The Chargers] came ranked like 25th in third downs and we were top 10," Broncos coach Vance Joseph said. "That was embarrassing how we played third downs. Honestly, it was embarrassing ... but it’s a passing league, you know that every week when you line up, your guys have to play with confidence and great technique, and keep playing through things, with confidence, because there is no place to hide."