The departure from the previous season was unmistakable.

The Patriots’ 2015 season crashed against the rocks of a failed 2-point conversion in the AFC Championship game against Denver, when Tom Brady’s pass intended for Julian Edelman at the goal line was tipped and then intercepted.

With that play, Denver advanced to the Super Bowl with a 20-18 victory; two weeks later, the Patriots watched from their couches as Peyton Manning hoisted the Lombardi Trophy.

That outcome stood in marked contrast to what transpired this past Sunday when the Patriots won their frantic race against both time and the scoreboard with a pair of fourth-quarter touchdowns that were punctuated by successful 2-point conversions.

Had the Patriots failed to convert either opportunity, they’d have lost the Super Bowl. Instead, in becoming the second team to convert a pair of 2-point attempts in the title game (the first was the 1994 Chargers, who still lost in a blowout), the Patriots pushed the game to overtime and claimed a 34-28 victory.

The back-to-back successes — the first on a direct snap to James White, the second on a quick pass to Danny Amendola — represented the first time in the 16 seasons since Brady became the Patriots quarterback that New England successfully converted a pair of 2-point attempts in one game.

There had been five previous instances in the Brady era in which the Patriots went for 2 twice in a game; in all of them, they failed on at least one.

Going back to the NFL’s adoption of the 2-point conversion in 1994, there had been just one instance when the Patriots successfully went for 2 twice in the same game — on Oct. 6, 1996, in a 46-38 shootout win over the Ravens. The second pushed their lead from 22 to 24 points in the fourth quarter — hardly the sort of pressure that New England faced in the Super Bowl.

In sum: In 408 games since the advent of the 2-point option, the Patriots had multiple drives that resulted in 8 points in just 0.2 percent of those contests.

How rare was it for the Patriots to pull off such a trick in the context of the entire NFL?

■ Across the league this year, in 523 regular-season and playoff games, teams averaged 0.1 successful 2-point conversions per game. That sounds low, but it actually marked the highest rate since 1994.

■ There were a total of 13 contests, including the Super Bowl, with multiple 2-point conversion attempts (roughly one out of every 40, or 2.5 percent). Teams were actually successful on multiple 2-point conversions in three of those 13 games, though in one of those, the Raiders were 2 for 3.

■ According to Pro-Football-Reference.com, teams were successful on exactly half of their 2-point attempts this year, suggesting that an average team had a 25 percent likelihood of going 2 for 2.

That 50 percent rate has been fairly steady over time. Over the last five years, teams have been successful on 49.8 percent. Under Brady, the Patriots had been slightly more successful, converting 51.4 percent since 2001 (excluding Matt Cassel’s three attempts), meaning the likelihood that they’d convert both attempts in a game was roughly 26.4 percent.

Ultimately, the Patriots’ unprecedented comeback in the Super Bowl required the perfect alignment of any number of low-probability events. While things such as Julian Edelman’s circus catch or the faulty play-calling that knocked Atlanta out of position for a potential game-clinching field goal will command the most attention, there are plenty of subtle details — such as the Patriots’ unusual success on 2-point attempts — that merely add to the magnitude of New England’s stunning triumph.

Alex Speier can be reached at alex.speier@globe.com.