Is this Peyton Manning's best defense ever?

— -- Peyton Manning's nine touchdown passes and 17 interceptions this season have Hall of Fame company. Johnny Unitas put up the same totals over his final 14 starts. Dan Marino had nine scoring passes with 15 picks in his final nine starts. Brett Favre went out with 10 touchdowns and 18 interceptions in his final dozen starts.

While there's nothing new about future Hall of Famers going out with statistical whimpers, most of the greats have not had championship-caliber defenses on their side to ease them into retirement. Manning does, which explains why the 39-year-old quarterback stands one victory away from the Super Bowl. Denver's defense allowed the Broncos to earn the AFC's top playoff seed with a 12-4 record even though the team ranked 25th in Total QBR (46.7) and 31st in passer rating (76.3). Those were NFL lows within the 12-team playoff field.

Manning has never needed a defense as much as he needs this Broncos unit, but he had some very good ones on his side previously, both in Denver and Indianapolis. This 2015 Denver defense has to rank near the top. Should it be No. 1 among all the defenses associated with Manning since his 1998 debut with the Colts? Let's take a look at my top five.

Before we get to the list, I'd be remiss if I failed to mention the 2006 Colts defense -- Manning's only Super Bowl-winning unit. That defense notoriously allowed 375 yards rushing to the Jacksonville Jaguars during a dispiriting 44-17 defeat in Week 14. It finished the regular season ranked 31st in ESPN's expected points added (EPA) metric as injuries sidelined safety Bob Sanders. But when Sanders returned to the lineup and linebacker Rob Morris became a starter late in the season, that Colts defense delivered Indy its lone Super Bowl title.

Manning tossed three touchdown passes and seven interceptions during the playoffs that season. His passer rating (70.5) and QBR (54.2) during that four-game postseason stretch fell far below his league-leading figures for the regular season. The Colts won the Super Bowl anyway, and for that they can thank their defense. Opposing quarterbacks Tom Brady, Steve McNair, Rex Grossman and Trent Green matched Manning's totals for touchdowns and interceptions that postseason. Their combined passer rating (62.8) and QBR (12.5) against the Colts reflected Indy's quick reversal on defense that season.

To this day, the 2006 Colts rank second out of 120 playoff teams over the past decade in defensive EPA per game during a single postseason. Only the 2008 Ravens rank higher. But because that Indy unit was only 31st during the regular season, I kept it off my list of top-five Manning-affiliated defenses.

The 2015 Broncos are No. 1 for a few reasons. The other high-ranked defenses could count on Manning to produce at a high level most of the time. Many of the ones in Indianapolis were set up to rush the passer after Manning and the offense had built leads. This Denver defense has had to win despite its offense, and it has generally succeeded over a full season.

This Denver defense ranked first among the 17 Manning-affiliated defenses in EPA per game. ESPN's version of that advanced metric dates only to 2006, so to supplement the rankings below, I used a version developed by Pro Football Reference, which covers more years.

The top five

1. 2015 Broncos

Defensive EPA/game: +6.7 (1st among Manning's teams, counting playoffs)

Team PPG allowed: 18.4 (3rd among Manning's teams, counting playoffs)

Top performers: OLB Von Miller (11 sacks) leads a deep group of pass-rushers, particularly when OLB DeMarcus Ware (7.5 sacks) is healthy. DL Derek Wolfe, LB Danny Trevathan, LB Brandon Marshall, S T.J. Ward, CB Chris Harris Jr., CB Aqib Talib and DL Malik Jackson are also key contributors.

Signature game: 26-23 victory at Cleveland in Week 6. This performance made it clear that the Broncos would have to win in spite of their Manning-led offense, not because of it. The Browns picked off Manning three times, returning one of those interceptions for the go-ahead touchdown in the fourth quarter. Broncos safety David Bruton picked off Josh McCown's pass to help force overtime after Cleveland crossed midfield.

2. 2012 Broncos

Defensive EPA/game: +5.4 (2nd)

Team PPG allowed: 19.2 (6th)

Top performers: Miller (18.5 sacks), Elvis Dumervil (11 sacks) and CB Champ Bailey were the headliners on this defense, which scored five times on interception returns.

Signature performance: 35-24 victory over San Diego in Week 6. A pick-six interception off Manning and a short touchdown drive following a Broncos fumble helped San Diego take a 24-0 lead into halftime. The Broncos' defense finished with four sacks and four interceptions off Philip Rivers. Dumervil forced a Rivers fumble that cornerback Tony Carter returned for a touchdown. Harris put away the game with a pick-six in the final minutes.

3. 2005 Colts

Defensive EPA/game: +3.9 (3rd)

Team PPG allowed: 15.8 (1st)

Top performers: DE Robert Mathis (11.5 sacks) and DE Dwight Freeney (11 sacks) weren't the only playmakers. LB Cato June picked off five passes, scoring on two of them.

Signature performance: 26-7 victory over Pittsburgh in Week 12. The Colts held the eventual Super Bowl-champion Steelers to 10 first downs and 197 total yards on 54 plays, picking off Ben Roethlisberger twice and sacking him three times.

4. 2007 Colts

Defensive EPA/game: +2.5 (5th)

Team PPG allowed: 17.1 (2nd)

Top performers: Sanders was first-team All-Pro, while S Antoine Bethea earned Pro Bowl honors. Mathis had seven sacks, but injuries limited Freeney to nine games.

Signature performance: 23-21 defeat at San Diego in Week 10. The Chargers scored on the opening kickoff and picked off Manning six times, but linebacker Gary Brackett got the Colts to within 23-21 early in the fourth quarter with a fumble recovery in the end zone following a sack of Rivers. After the Colts' offense failed to convert the ensuing two-point try, linebacker Clint Session picked off Rivers to set up another Indy scoring opportunity -- only to have Adam Vinatieri miss a 29-yard field goal try with 1:34 remaining.

5. 1999 Colts

Defensive EPA/game: +2.7 (4th)

Team PPG allowed: 20.7 (8th)

Top performers: DE Chad Bratzke (12 sacks), DL Ellis Johnson (7.5 sacks) and LB Cornelius Bennett (five sacks)

Signature performance: 44-17 victory over Philadelphia in Week 11. The Colts held the Eagles to 212 yards and 13 first downs, building a 44-3 lead through three quarters. Eagles rookie Donovan McNabb completed 19 of 36 passes for 165 yards with two interceptions.