Sometimes, you can tell in three plays.

Three plays are all first-year Denver Broncos’ head coach Vance Joseph needed to realize he inherited a really good defense. Three plays are all the Denver defense and the No Fly Zone needed to show their old coach John Fox the Chicago Bears’ new quarterback had no shot.

On the third play of the Broncos’ opening preseason game, Bears quarterback Mike Glennon dropped back in the pocket, was harassed by outside linebacker Kasim Edebali, who was starting in place of Von Miller, and simply threw it up for grabs in quadruple coverage.

Broncos cornerback Chris Harris Jr., a three-time Pro Bowler and defending first-team All Pro selection, caught the pop-up pass at midfield and ran untouched to the end zone for a 50-yard interception return.

The Broncos were up 7-0. Take the rest of the night off, guys.

"I said, "We're done, coach, I'm out of here,'' Harris said, smiling. "No, coach said, that's it, you're done.''

The Bears went ahead thanks to rookie quarterback Mitch Trubisky but the Broncos had their own rookies in quarterback Kyle Sloter and running De’Angelo Henderson to rally back for a 24-17 win in the preseason opener for both teams before only 43,946 at Soldier Field.

Harris thinks he will be able to get more interceptions this year because of tweaks new coordinator Joe Woods has employed.

“I love the format we have,'' he said. "We have more zone. I get to read more. I get to read the quarterback more. It was the same kind of pick I had against Paxton in the scrimmage (on Saturday). Jumping the same route.''

The second half became an impressive battle of two rookie quarterbacks: Trubisky, the No. 2 overall pick in the 2017 NFL Draft, and Sloter, an undrafted afterthought from Northern Colorado.

Trubisky rallied the Bears from a 10-0 deficit to 17-10 fourth quarter lead by completing 13 of 14 for 123 yards at one point. Sloter followed by completing 4 of 5 for 70 yards including a game-tying, 47-yard touchdown to wide-open rookie Isaiah McKenzie. Sloter and McKenzie are roommates during training camp.

The Broncos' preseason dress code did require a tie. The only player to wear a sports coat and tie on the trip: Sloter, the game 1 hero.

On third down and the Broncos just trying to get in long field goal position for Brandon McManus, Henderson burst up the middle for a 41-yard touchdown inside the 2-minute warning.

"It was an inside zone read play,'' Henderson said. "It opened up pretty good -- the defenders were playing pretty deep. After I got the ball I knew i had a chance to make something happen. Got it, saw a little crease, hit it.''

In The Great Quarterback Competition, Trevor Siemian completed 6 of 7 passes for 51 yards. He generated 3 points in three possessions. Paxton Lynch was 6 of 9 for 42 yards with no points in four possessions. Lynch also scrambled four times for 11 yards. Sloter was 5 of 6 for 94 yards with a touchdown.

Can Sloter get some love? Perhaps, on the practice squad he can if he makes it that far. Sloter has done nothing but complete passes during his rare, third-team reps in the offseason and training camp and he stepped it up when the lights were on Thursday night.

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Denver’s second-string defense continue to apply pressure on Glennon and Mark Sanchez, holding the Bears scoreless late in the second quarter when Trubisky engineered a 50-yard touchdown drive in the final 1:42 of the game.

Trubisky was 4 of 4 for 24 yards in his opening series, including a 2-yard touchdown flip to a wide open Victory Cruz, the former New York Giants’ star.

Siemian, the Broncos starting quarterback, overcame his own protection breakdowns to engineer a 10-play, 60-yard drive before settling for a Brandon McManus field goal on the Broncos’ first offensive possession.

The drive started with Siemian hanging on to the ball a tick longer than usual off a play fake and as he looked for an open receiver and Bears’ edge rusher Leonard Floyd beat new Broncos right tackle Menelik Watson for a 7-yard sack.

"A horrible first play, obviously,'' Watson said. "Used the wrong technique in that situation. He got slippery. I tried to re-set, missed it. Really, disappointed. When you have a bad play like that at the start, it dampens everything else. But after that we started running the ball, knocking the guys back five, six yards.''

But C.J. Anderson, who had a nice opening drive, got 6 yards back on his first carry and then Siemian drilled a hook pattern to a well-covered Demaryius Thomas for 11 yards and the first down.

The drive reached the Bears’ 20, but on third-and-7, Siemian was lucky to get rid of the ball in the face of a fierce pass rush and McManus booted a 38-yard field goal.

Anderson rushed for 21 yards on five carries on the opening drive. He came out and was replaced by Stevan Ridley.

Winn injured

The most negative aspect of the game for the Broncos was watching defensive lineman Billy Winn have to get helped on to a cart and driven off the field. The Broncos fear the veteran Winn has a torn ACL. More will be known through an MRI test Friday morning.