How Brady's late-career performance stacks up against other all-time greats

With his 40th birthday looming in August, Tom Brady showed no signs of decline en route to his fifth Super Bowl win.

Brady, who intends to play into his mid-40s, was clinical after serving a four-game suspension, sporting a 28:2 touchdown-to-interception ratio as the New England Patriots cruised to a league-best 14-2 record, before capturing Super Bowl LI in overtime against the Atlanta Falcons.

Entering his 18th professional season and his age-40 year, we assess where Brady's 2016 ranks among the best age-39 campaigns in NFL history, and consider how he'll fare in his fifth decade.

Tom Brady

Age-39 season

Brady had one of the best seasons of his decorated career in the last year of his 30s, remaining clinically efficient throughout. He returned from a four-game sanction no worse for wear in 2016, commanding the Patriots' offense at a furious pace and eviscerating opponents with an unmatched release.

Although Brady wasn't nearly as efficient in the playoffs as he was during the regular season, he still performed at a superstar level, tossing seven touchdowns against three interceptions, with a 65.5 percent completion rate. Brady is reticent to consider Super Bowl LI his best performance, but he diced apart the Falcons' defense on 43-of-62 passing for a Super Bowl-record 466 yards, with two touchdowns versus one interception, which was returned for a score.

It's difficult to account for inevitable regression, but Brady is well-positioned to be the best quarterback ever to take the field at age 40 or older, with few indications that he'll plummet anytime soon.

Brett Favre

Age-39 season

Favre's lone season with the New York Jets will be forgotten among the rest of his canonical career. The Jets improved by five wins with him under center, but failed to make the playoffs, posting a 9-7 record.

The raw numbers belie Favre's steep decline during the latter half of the season, with the Jets losing four of their last five games. He was certainly at fault for New York's descent into no man's land, throwing four touchdowns against 10 interceptions during the team's final six contests.

He lost favor with the organization and told the Jets he intended to retire, and was subsequently released. Projecting how Brady will compare to Favre is a difficult task, however, as the latter recovered incredibly during his age-40 season.

Age-40 season

Favre returned to excellent form after signing with the Minnesota Vikings in August 2009, earning Pro Bowl honors for the 11th and final time. Unfortunately, his season will be best remembered for a critical interception thrown during the NFC Championship Game against the New Orleans Saints, which led to an overtime loss.

The Hall of Famer never recovered from the costly mistake, completing 60.9 percent of his passes for 11 touchdowns against 19 interceptions in his age-41 season. It'll be difficult to project whether Brady will encounter similarly erratic swings in his performance after turning 40.

Peyton Manning

Age-39 season

Manning won Super Bowl 50 with the Denver Broncos in the final game of his career - a fitting tribute to one of the greatest careers in NFL history. Lionizing him for his contributions throughout his age-39 season, though, would be wrong.

The Broncos were successful due to their historically good defense in 2015, even if revisionist history gives Manning equal footing. Despite missing six games, he threw 17 interceptions - second only to Jacksonville's Blake Bortles - while failing to complete more than 60 percent of his passes for the first time since his rookie year.

Manning and Brady are inextricably linked, and while the former's retirement makes it impossible to compare their age-40 seasons, the Patriots star may reconsider playing for an extended period if he experiences a rapid decline.

Warren Moon

Age-39 season

Moon threw 33 touchdowns during the 1995 season with the Minnesota Vikings, the most ever by anyone in their age-39 campaign, and was named to his eighth consecutive Pro Bowl after completing a league-high 377 passes. Before Brady triumphed in 2016, he was the standard-bearer for quarterbacks over the age of 40 in the modern era. In spite of Moon's heroics, though, the Vikings missed the playoffs with an 8-8 mark.

Age-40 season

Moon started the first eight games of the season, but missed the remainder due to a broken collarbone. The veteran quarterback bristled at the idea of a pay reduction with Brad Johnson named the starter, signing with the Seattle Seahawks before the 1997 season.

At 41, Moon rebounded during his first year with the Seahawks, throwing 25 touchdowns versus 16 interceptions, and earning Pro Bowl honors for the ninth and last time, but the team missed the playoffs. He failed to replicate this form during the last three seasons of his career, playing in 12 games following the 1997 season.

Prior to his 17-year NFL career, Moon was one of the most dominant players in CFL history, winning five consecutive Grey Cups, and the totality of his career should be considered when using his output to project Brady's future. Brady will likely post unprecedented numbers in his 40s, but Moon is the closest thing to sustained greatness at that age.