INDIANAPOLIS — Areas of interest in the Indianapolis Colts’ Sunday meeting with the Broncos in Denver’s Empower Field at Mile High. Kickoff: 4:25 p.m. Broadcast: CBS4. Spread: Broncos by 4½. History lesson, Part I: The Colts lead the overall series 15-14, an edge achieved on the strength of a 3-0 record versus Denver in the playoffs. The Andrew Luck-led Colts whipped quarterback Peyton Manning and the Broncos in the 2014 postseason, while Manning absolutely destroyed Denver in 2003 (41-10) and ’04 (49-24; it was 35-3 at the half). In the two games, Manning passed for 835 yards and seven TDs. In the ’04 game, wideout Reggie Wayne set a club playoff record with 221 receiving yards on 10 receptions. Wide receiver T.Y. Hilton topped him in the ’13 playoffs with 224 yards against Kansas City. The Colts have won their past two meetings with the Broncos, including that unsightly 12-9 overtime decision at Mile High in week 5 of the 2022 season. History lesson, Part II: It’s hard to purge that ’22 meeting from the memory. Kicker Chase McLaughlin was the Colts offense with four field goals. His 31-yarder with 5 seconds remaining forced overtime, and his 48-yarder at the 5:50 mark of OT ended the Thursday night street fight. Corner Stephon Gilmore sealed things by deflecting a Russell Wilson pass in the end zone on fourth-and-1 at the Indy 5-yard line. The game marked just the 11th time since 1984 the Colts won a regular season game without scoring a touchdown, and the first time since a 9-6 win at Cleveland in 2003. History lesson, Part III: Quarterback Joe Flacco will stand on the sideline as Anthony Richardson’s backup, but trust us, at some point he’ll have a flashback moment. He’s started 210 games in his 17-year career, and the one that ranks high on his highlight list is the 2012 AFC Divisional meeting with the Broncos at Sports Authority Field at Mile High. His Baltimore Ravens trailed Manning’s Broncos 35-28 with time running out. Everything changed when Flacco hit wide receiver Jacoby Jones for a 70-yard touchdown with 31 seconds remaining. It was one of those desperation throws that was answered when Broncos’ defensive backs Tony Carter and Rahim Moore botched their coverage of Jones. The Ravens went on to win 38-35 in a second overtime on kicker Justin Tucker’s 47-yard field goal. The improbable win over Denver was the catalyst as Baltimore won the AFC Championship with a 28-13 win at New England and Super Bowl XLVII against San Francisco, 34-31. Flacco was named Super Bowl MVP after passing for 287 yards and three TDs. He was a free agent after the season, and the Super Bowl drive led to the Ravens signing Flacco to a six-year, $120.6 million contract. He was the NFL’s highest-paid player until Aaron Rodgers and Matt Ryan leap-frogged him a short time later. Playoff picture: Must-win talk is casually thrown about, but let’s not kid ourselves. Sunday’s meeting with Denver is as MUST as it gets for the Colts. “Shoot, if you can’t get up for a game like this, you’ve got problems,’’ Colts coach Shane Steichen said. The 8-5 Broncos hold the No. 7 spot in the seven-team AFC playoff chase, and 6-7 Indy is at No. 8. With a win, the Colts’ chances of earning their first playoff spot since 2021 rise to 65%, according to the New York Times’ playoff simulator. They fall to 11% with a loss. The Colts face a favorable closing schedule: Tennessee (3-10), at the New York Giants (2-11), Jacksonville (3-10). Denver’s final three games are more perilous: at the Los Angeles Chargers (8-5), at Cincinnati (5-8), Kansas City (12-1). But that only matters if the Colts take care of business in Denver and gain the head-to-head tiebreaker. *Richardson in the spotlight: Richardson heads into his 14th career start and it’s undeniably his biggest moment. Even if he’s reluctant to admit it. “I wouldn’t necessarily say the biggest one of my career,’’ he said.  “I feel like every game is a big game. The last one we just played was a big game. “So, every game I approach is a big game to me. So, I'm just trying to get a ‘W.’” That’s probably the appropriate approach. As consequential as Sunday is, Richardson and the Colts can’t fall into the trap of trying to do too much. Having said that, Richardson must be at the top of his developing game. He’s got to remain a serious complement to running back Jonathan Taylor in the run game and orchestrate an efficient pass game that takes occasional shots downfield to Alec Pierce and Josh Downs, who returns after missing one game with a shoulder injury. Since returning from his two-game benching, Richardson has 141 yards and three TDs on 29 rushes/scrambles. In the win over New England prior to the bye, Taylor worked his way for 96 yards on 25 carries, and Richardson added 48 yards and one TD on 10 attempts. What’s been missing are explosive runs. The Colts have just eight runs of at least 10 yards over the last three games, and Richardson has accounted for six of them. Taylor’s longest runs during that stretch — 60 attempts — have been 10-and 14-yarders. His per-game averages over the last three games: 3.8, 3.2, 2.4. An offensive line combo of Bernhard Raimann, Quenton Nelson, rookie Tanor Bortolini, Mark Glowinski and rookie Matt Goncalves needs to win the line of scrimmage. Road block in Denver: It shapes up as strength vs. strength. The Colts should lean heavily on a Taylor-Richardson run game while the Broncos boast a defense ranked No. 8 overall and No. 6 against the run. Denver is allowing just 84.7 yards per game on the ground and 3.8 per attempt (No. 3 in the league). During its three-game win streak, Denver has yielded 65.3 rushing yards per game and 3.3 per attempt. Just how good?: It’s difficult to gauge the true strength of the Broncos’ defense and their team overall. Maybe they’re as strong as advertised. Maybe not. Denver allowed a season-high 552 yards in its most recent win, a 41-32 decision over quarterback Jameis Winston and Cleveland. It allowed 369 the previous week in a win at Las Vegas. We’re just throwing out the fact 8-5 Denver has one victory over a team with a winning record. That was a 26-7 win at Tampa Bay (7-6) in week 3. The combined record of the other seven victims: 24-67 (.264). And, yes, the 6-7 Colts haven’t exactly whipped the NFL’s best. The only team they’ve beaten with a winning record is the 10-3 Pittsburgh Steelers. The other five teams share a 19-46 record (.283). What can’t be denied is the disruptive nature of Denver’s defense. It loves to blitz and has piled up a league-high 47 sacks — 16 in the last four games — and 100 pressures, which have contributed to 12 interceptions and 18 takeaways. Linebackers Nik Bonitto (11 sacks) and Jonathan Cooper (8) are the catalysts for pressuring the quarterback, while cornerback Patrick Surtain II is the playmaker on the back end with three interceptions and nine passes defended. Richardson needs to take his shots — Steichen’s offense is reliant on explosive plays — but avoid the game-changing mistakes. Nix Nix: Get it? Bo Nix has been one of the NFL’s mild surprises this season. Coach Sean Payton invested the 12th overall pick in the April draft on an Auburn/Oregon product with 61 collegiate starts and then named him his opening-day starter. It was quite the honor. The last rookie QB to start opening day for the Broncos? John Elway in 1983. Nix hasn’t disappointed Payton or Broncos’ fans. Among rookie QBs, he ranks first in offensive touchdowns (22), completions (277), passing yards (2,842) and passing TDs (17). He’s completing 63.8% of his passes and his 42 completions of at least 20 yards are tied-8th in the league. He’s also a threat to escape pressure and extend drives with his lets. Nix has 304 yards and four TDs on 67 rushes/scrambles. “That’s something we’ve got to be aware of because a lot of his explosive plays come off of that,’’ defensive coordinator Gus Bradley said. And the winner is: Broncos 27, Colts 17. It’s quite a matchup pitting young QBs who have started 13 career games. Richardson has kept the Colts’ season relevant by leading fourth-quarter comebacks against the Jets and Patriots in two of the last three games. He’s been clutch when it matters but has lacked game-long consistency and efficiency. Nix is emerging as the future of the Broncos. Can the Colts contain Nix? Can they protect Richardson and give the run game room to operate? We’re expecting Denver’s defense to create a few game-changing plays. You can follow Mike Chappell on Twitter at @mchappell51.