The old debate about whether it’s better to be lucky or good doesn’t apply to the Green Bay Packers, who are both. Quarterback Aaron Rodgers and his offense have completed three Hail Mary passes in a little more than 13 months, most recently stunning the Giants with a 42-yard touchdown to Randall Cobb to end the first half of last weekend’s wild-card meeting, which Green Bay went on to win 38–13, but led just 7–6 before that strike.

The play did more than energize the offense and spark a second-half surge: It firmly established the Packers as the unquestioned masters of the Hail Mary. Specializing in an event with such a low-probability outcome might seem impossible, like becoming an expert at winning the jackpot via scratch-off ticket. But the combination of a once-in-a-generation quarterback talent, pass catchers who train for the moment, and, yes, some luck, has made these remarkable results seem routine. Ahead of the team’s marquee divisional-round matchup with the Cowboys in Dallas on Sunday, I went to Green Bay to find out how the Packers keep making the most unlikely play in sports work.

Phase 1: Before the Snap

Sometimes it’s impossible to know if a thing will work until you see it in action: shark cages, airbags, stand-up comedy. For the Packers, the Hail Marys they attempt in games are a bit like that. The team practices the prayers every Saturday without full pads, and to prevent injury the pass catchers restrain from jumping fully. The drills primarily center on positioning and boxing out. Rodgers is not the quarterback for every session. Tight end Richard Rodgers, who caught a 61-yard Hail Mary against Detroit last season, acknowledges that it’s hard to know just from these drills what will work in a real game, and that in fact the test runs can be most useful for helping the defense improve on these plays.

While these practice sessions are not perfect game-day simulations, they remain crucial. When Rodgers is the one throwing, the pass catchers learn how to read his high, deep ball. The reps also allow Rodgers, who prides himself on his muscle memory, to learn how to throw a pass deep enough to hit the end zone, but not so deep that it goes out of the end zone. The balance between chucking it down the field and keeping it in play is delicate, but growing comfortable with that reality is why Rodgers knew that with the temperature in the teens and the wind at just 7 mph in Sunday’s wild-card game, he wouldn’t throw the ball out of play. His precision comes from practice.

"I think one of a quarterback’s strengths can be muscle memory and locking in a feeling about throws," Rodgers says. "Whether it’s throwing on the run into a tight window, or throwing a route [short to the outside], it’s no different with a Hail Mary — you have to understand how much effort you have to put into the throw and then marry that with the height you want to throw it at.

"You lock away that muscle memory, you learn how to do it moving left, moving right, with the wind moving directionally. You lock that away and then you remember every situation."

Over the last two seasons, 101 pass attempts have occurred with six seconds or less to go in a half or game and with the offense at least 40 yards from the end zone. Six of them resulted in touchdowns — and Rodgers has accounted for half of those scores.

That’s in part because the practice sessions also facilitate a mind meld between quarterback and receiver, with the wideouts gaining the ability to recognize where Rodgers’s passes will go. Receiver Jeff Janis, who has been on the field for two of the Hail Marys and caught the 41-yarder against Arizona that forced overtime in last season’s divisional round, noticed in practice that Rodgers’s high passes always look like they’re going farther than they ultimately do. It may sound obvious, but it’s key: No one can judge Rodgers’s passes as well as the people who’ve seen them the most.

"Once the nose starts dipping, it goes down really fast," Janis says. "Aaron throws a different style of ball. The defense has a harder time judging it. You have to keep that in the back of your head always when you’re near the end zone."

The ball goes so high, Richard Rodgers says, that during an unsuccessful Hail Mary attempt against Tennessee earlier this season, he watched the stadium video board while running his route to see where the ball was heading. He had an epiphany as he was running: "The passes go so high that looking at the video board is actually what you should do every time." He explains with a laugh that it’s hard to monitor the ball as you’re running, so to better see the launch angle and gauge the timing of the play, it can help to quickly glance up at the board that’s commonly behind the end zones in stadiums.

Even with consistent planning, things rarely come together perfectly on these attempts. When they do, though, it’s one of the most exciting moments the NFL can offer.

Phase 2: After the Snap

Rodgers has a confession: He doesn’t know exactly where he’s throwing the ball. He possesses supernatural arm strength — he can throw the ball 75 yards without pads on and 70 with them on, he says — so on these plays, he’s not stressing the distance; he’s just focusing on dropping the ball into a cluster of players whom he trusts to know how to react. Delivering the ball with pinpoint accuracy to a specific player isn’t as important as releasing a high ball and keeping it in bounds for a group of receivers who understand how to improvise.

"There’s a typical dispersion of the guys and you are throwing the ball to a spot," Rodgers says. "It’s not like I’m saying, ‘I’m going to throw this, everyone’s going to misjudge it, and Randall Cobb will catch it in the back of the end zone.’"

Proving that point: The exact intended play outcome has never come to fruition. There is only one Hail Mary drawn up in the Packers’ playbook. It places two receivers on one side, one on the other (the sides of the field can vary), and ensures that a tight end is ready to go out for a pass unless the defense implements the rare tactic of blitzing against a Hail Mary. (Aaron Rodgers kept Richard Rodgers in to block against Arizona when he realized the Cardinals were going to bring heavy pressure.) The tight end, provided he’s running out for the pass, is supposed to finish the play near the front of the end zone. But receiver Davante Adams — he of the 39.5-inch vertical jump at the combine, tied for third best among receivers in 2014 — is the play’s primary target, and should wind up in the middle of the end zone. Adams is supposed to outjump everyone, and his fellow receivers (such as Cobb) are supposed to box out "and give our jumper a little bit of space to jump," Cobb told reporters this week.

The ideal is for Rodgers to throw the ball six seconds into the play, which is enough time for the receivers to get downfield, but not so long that it makes it difficult for offensive linemen to hold their blocks. "Teams sometimes only bring three guys," says center Corey Linsley. "So you have to help out where you can, stay active." Sometimes, that timing has to change: When the Packers were trailing the Lions 23–21 late in their December 2015 contest, for example, Rodgers knew that he had to tweak the play because his receivers were tired after running "go routes" (straight-ahead routes, as fast as possible) on the three prior plays. "They needed to go 61 yards, which would take a sprinter six seconds," Rodgers says. So he bought time with his legs and threw the ball after about eight seconds instead.

The Packers so successfully execute Hail Marys in part because they plan on things failing to go as planned. And despite being the central receiver in the play, Adams has never caught one of Rodgers’s Hail Marys. "I’m the primary guy and defenses generally know that, so they surround me and they get on my back," Adams says. "My job is to get off the ground as high as possible."

Rodgers says Adams misjudged his pass in Detroit — and it actually helped: "He set the launch point about 7 yards back in the end zone, behind the play, so Richard was able to go into the front of the play with really no one around him."

With the Packers’ best-laid plans sometimes crumbling, they’ve had to rely on improvisation once the play breaks down. In the six-or-so-second span before Rodgers throws the ball and the few seconds during which the ball hangs in the air, players’ roles can change dramatically. After the snap in Arizona last January, for example, Janis, who started on the left side, was supposed to move to the right of the field. Rodgers wanted to roll out to the right, but the Cardinals were bringing pressure up the middle, and with the pocket collapsing he had to go to his left instead. "Aaron got flushed out of the pocket my way; I happened to look back as soon as it happened," Janis says.

That improvisation by quarterback and receiver alike is noteworthy. But nothing’s more impressive than Rodgers throwing the ball.

Phase 3: As the Pass Comes Down

The players who’ve caught Rodgers’s Hail Marys vividly remember the moment they knew it was actually going to happen. Richard Rodgers was shocked to discover so much open space on his play. "There was no one in front of me," he says. "Davante, Randall, James [Jones] did a great job of boxing out the guys."

Janis says that on his Hail Mary score, he noticed that there were two defenders deep in the end zone, meaning a pass thrown anywhere in front of them could be caught. "I couldn’t believe it," he says.

Cobb was stunned by how simple it all was, a rarity on Hail Marys. Most quarterbacks’ Hail Marys, Cobb told reporters, are tipped, causing chaos to ensue. But Rodgers’s ball was so hard to read that defenders weren’t even close. "Very unusual," Cobb said when asked about catching the rare back-of-the-end-zone Hail Mary. "I guess everyone but me [misjudged]." He added that the Packers’ ability to convert these plays is "unbelievable."

Defenders struggle to position themselves properly because doing so is no easy task. "Hell yeah, it’s hard to read," says Jared Cook, the tight end on the field for the most recent Hail Mary. "It’s like a punt. But we’re more used to reading these balls, and the defense isn’t."

It was clear that the Giants had lost track of the pass on Sunday: "That ball was overthrown," Giants safety Landon Collins told reporters after the game. "The ball was really in the back of the end zone and we didn’t think anybody had a chance to get it, but [Cobb] is in there to play."

Michael McBeath, a psychology professor at Arizona State, studies how a would-be recipient judges a catch — in football, in baseball, even dogs with Frisbees. He says that though it may not seem intuitive, defenses are at a massive disadvantage in Hail Mary situations. Offensive players just have to look for the ball once they are set and ready to receive the catch; defenders have to watch the receivers and the ball at different points in the play to keep pace and avoid committing interference. The key to the Hail Mary as it’s coming down, McBeath says, is a receiver keeping his eyes on the ball at all times and never wavering; that way, the object will appear to be traveling in a straight line and thus be easier to judge. If he takes his eyes off for one moment, McBeath says, the object will appear to be traveling off of its path. It’s why outfielders who watch the wall and the ball during a pursuit can fail — in attempting to track their surroundings, they can lose the ball’s flight path.

Janis agrees, saying that locking onto the ball in the final few seconds of the play after turning back toward the line of scrimmage is crucial to securing the pass. But Rodgers’s heroics, which almost always feature rollouts before the pass, make focusing fully on the ball challenging for some not on the field: those producing the television broadcast. Packers games are already hectic for TV crews due to Rodgers’s tendency to quick-snap the ball to try to catch defenses with 12 men on the field, but Rich Russo, a game director for Fox, says Rodgers is one of the hardest players to follow in a Hail Mary situation because of all the possibilities.

"I think it’s really about discipline," Russo says. "He’s such a great athlete and he’s going to escape the pocket, so the camera guys have to have discipline. You can’t go for any pump fakes on the play. It’s a stressful situation for camera operators — fourth-and-2, six seconds left — they could possibly have run a quick out and tried to kick a field goal, but I was saying, ‘Watch the Hail Mary,’ and our camera operators are so good at what they do.

"It’s a complicated play — you need to have cameras at the goal line, cameras go to the end line, because you don’t know what’s going to happen down there. It could ricochet off guys, it could maybe not go into the end zone. Randall Cobb only just got his feet in bounds."

Also facing pressure in these moments: the officials, who must make sure no penalties occur. The contact in the end zone during these scrums is one of the murkiest things to officiate. After the Giants game, Cobb acknowledged to reporters that he "nudge[d]" the defenders, saying, "[It was] just a little bit. Not too much. They didn’t throw a flag, so I guess it was enough."

Rules expert Jim Daopoulos says there’s a very high bar for pass interference on these plays: "We know there’s going to be a lot of contact, but as long as they are legitimately trying to get the ball, there won’t be a flag," says Daopoulos, who was an NFL referee for 11 years and the supervisor of officials for 12. "Everyone has an opportunity to go for the ball. It’s a huge scrum, but the only way there will be a flag is if someone isn’t playing the ball and really trying to gain an advantage — a grab or a jerk of a guy out of the way."

Phase IV: After the Touchdown

When the officials’ hands go up into the air instead of reaching for their flags, madness ensues. Catching a pass like this often feels great — but also terrible. "The play kind of hurt pretty bad, just falling down, I kind of messed up my back for a while," Janis says. "I was kind of hurt, so I couldn’t celebrate too hard, but inside I was pretty excited."

Teammates swarmed Richard Rodgers in a dogpile after the win over Detroit, and he later told the team website that he thought he was going to die at the bottom of it. Janis says he couldn’t even find Aaron Rodgers after his touchdown. "He was too busy celebrating with everyone else," Janis says. "He found me on the team plane, shook my hand, and said good job."

Corey Linsley didn’t even see the touchdown last week — he was busy blocking Giants and then noticed the crowd roaring. "I was like, ‘This is amazing. A third one?’"

Yes, a third one. Rodgers and his receivers have turned a flukey event into something repeatable, and now the Cowboys are fretting over the prospect of another Hail Mary attempt on Sunday. Rodgers’s teammates, meanwhile, remain amazed at the success rate, but grow less surprised with each positive outcome. "Aaron is perfect for that," Cook says. "The play is a combination of timing, ball placement — and Aaron."