EAGAN, Minn. -- Adam Thielen knows he's going to get an earful from Stefon Diggs if he doesn't deliver.

We're not talking about what he does on the field, in practice or in games. This is something far more pressing, at least in terms of how Thielen helps Diggs set his day in motion.

Thielen has one job on his way into the wide receiver meeting room each morning at the Minnesota Vikings' TCO Performance Center.

"Diggs is going to have a cup of watermelon," Thielen, 28, said. "I have to grab it for him every time."

On the flip side, Diggs, 24, can list off the nitty gritty of Thielen's routine. Given the amount of time these two spend around each other during the season, memorizing each other's food preferences comes as easy as their recall of the playbook.

"I can tell you he's going to get at least two cups of coffee before 12 o'clock and if he does want something to snack on, he only eats healthy snacks," Diggs said. "He eats these nasty not-donuts -- "

Adam Thielen and Stefon Diggs combined for 155 receptions, 2,125 yards and 12 touchdowns last season. Scott W. Grau/Icon Sportswire

"Protein balls," Thielen interrupts.

"They're not donuts," Diggs continues. "They give you all the look and feel of a donut but they're ... gross."

The dynamic between the NFL's top receiving duo includes plenty of inside jokes, chops-busting and finishing each others sentences. It's a bond formed between Diggs and Thielen since their paths converged in Minnesota in 2015. They go together like peanut butter and jelly, serving as a complement to the other's success, each a star on his own but a true luxury for any team to have as a package.

They're two unlikely NFL stars from widely different backgrounds: Diggs, the five-star prospect turned fifth-round pick who became one of the league's richest receivers this offseason after signing a five-year, $72 million extension, and Thielen, a Minnesota State-Mankato product who rose from undrafted free-agent practice squad member to Pro Bowl receiver in four seasons.

What makes them great on the field is what has been built off it: A bond between two players in different places of their lives who have become the most important, versatile chess pieces in the Vikings' offense. How they got to that point came via a shared mindset of how they'd approach their goals, always chomping at the bit to reach the next pinnacle of success.

"I think that's carried us as long as it has because we want to win today," Diggs said. "We care about being in the moment, making each and every play rather than waiting for it. We're not going to settle for something less than the standard that we set.

"He won't accept some bulls--- out of me and I won't accept some bulls--- out of him. No bulls--- policy."

Mutual admiration

When asked to name the best Diggs catch he's seen, Thielen's choice isn't one you'd expect.

"We were playing in Chicago," Thielen said. "I don't remember what year it was (it was 2015), but he caught an inside breaking route and spun out of it and went for 40 yards and scored. I think it was to --"

"Tie the game," Diggs said, finishing Thielen's sentence.

Diggs led the NFL in contested catch rate last season (64 percent), according to Pro Football Focus. Thielen wasn't far behind (51.7 percent), and they combined for 31 contested catches on 54 opportunities and were the only teammates to rank in the top 10. Thielen excels at catching tight-window throws, like the one he caught for a TD in Green Bay in Week 2. The best example to Diggs came during a 2017 preseason game at Seattle.

Stefon Diggs' extension runs through 2023 and includes $40 million in total guarantees. Jamie Squire/Getty Images

"He had an over route where they're playing right underneath you in man coverage," Diggs said. "He caught it with someone draped over his back. I'm like, ‘Damn, that's a contested catch.' He makes a lot of those."

The consensus between the two is that Thielen has the better hands -- he has the second-most receptions (32) in the NFL through the first three weeks of the season. He had a team-best 91 catches and 1,276 yards last season.

But the way Diggs catches the ball sparks a fun conversation.

"I mean, he has a better chest," Thielen said with an emphatic laugh.

"He thinks I catch it with my body," Diggs said before demonstrating his receiving style compared to Thielen's.

"He likes to catch everything with his hands like this," Diggs said, forming a chest-high diamond-shaped window with his hands. "That's entirely too uncomfortable for me."

This, Diggs said pointing to his chest and stomach, is what he calls "the backboard."

"If it's in the radius of my chest area to my stomach, it's getting put on the backboard," said Diggs, who had 64 catches for 839 yards and 8 touchdowns in 14 games last season. "Anything outside or low, I have to put my hands up because it's out of reach."

They may bust each other's chops over how they prefer to catch the ball, but the one thing you'll find them in agreement on is how much they laud the other's ability to run routes.

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"I remember the first OTA practice seeing him run some routes and thinking ‘Ooh, this guy is going to be really good,'" Thielen said. "A lot of times you don't see that, doesn't matter when they're drafted, first round or not. You usually don't see guys come in and wow you. I knew when he came in and the way he played the game that he was something special."

That feeling was the same the other way around. In one of his first meetings as a rookie in 2015, Diggs recalled watching film that demonstrated a handful of routes the Vikings would run that season.

His role on the team was much different three years ago, but Thielen has long made his understanding of leverage and how to set up defenders with his eyes and body an art form.

"Adam was the best route runner we had," Diggs said. "I don't care what nobody says. I don't care who we're playing, he runs the best routes. This is who I want to watch. This is who I'm probably going to learn how to run routes from. This is who I want to be like."

'Can't give you that'

Thielen has been perfecting his craft off the field, looking to step his game up in ways already mastered by his wide receiver cohort.

"Any time I buy clothes, I tell my wife, ‘Does this look like something Diggs would wear?'" Thielen said. "And then I can buy it."

Honing his fashion sense brings Thielen one step closer to having the swagger of a guy who wears a diamond-encrusted Starbucks logo around his neck. But if he ever claimed to be the best dressed on the team, he'd hear Diggs utter his favorite expression, one that's well known in the receiver room.

"Can't give you that," the two say in unison, a phrase for calling someone on their bluff.

A former undrafted free agent, Adam Thielen had 91 catches for 1,276 yards last season. Joe Robbins/Getty Images

After his miracle catch against the Saints in the playoffs, Diggs was thrust into the national spotlight this offseason. He stars in a Geico commercial that plays off his sticky hands, and he made a cameo on "Celebrity Family Feud." Acting has sparked a new passion for the wideout; Diggs hopes his next on-camera appearance will be in a movie.

He also made waves by signing his mega-extension that's set to keep him in Minnesota through the 2023 season. His biggest cheerleader was the guy who sits next to him every day in the meeting room.

"I really am genuinely happy for guys that get paid and have success when they actually work their tails off," said Thielen, who with his wife Caitlin recently launched the Thielen Foundation, which focuses on supporting youth mental health initiatives. "He's a guy that goes out there and busts his butt every day in practice."

Thielen, like anyone with an Instagram account, got a glimpse into just how hard Diggs was grinding throughout the offseason.

"Everybody knows everything about Diggs," Thielen joked. "He puts everything on social media."

Diggs can't deny it. This is a ribbing he gets often -- one he enjoys dishing back.

"He'll give me a hard time," Diggs said. "He'll say something corny as usual and I'll just make fun of him. I know he's working out, I know he's doing his thing. So I'll say ‘How's training at ETS (the Minneapolis metro-area gym Thielen and his wife co-own)?' I make fun of him like they don't work as hard. Like regular people working out."

Show, don't tell

On a short week of preparation for the Los Angeles Rams amidst a gauntlet stretch in the first five weeks, Diggs is rather quiet at the moment. Before Thielen joined him in the players' lounge, Diggs has his gaze locked on his iPhone, taking solace in one of the rare moments during the day he has to himself.

When Thielen arrives, Diggs' body language changes entirely. Within minutes, they are cutting up and conjuring hearty laughs from each other.

Stefon Diggs wears socks featuring the face of teammate Adam Thielen during warmups before the Vikings' Week 3 game against the Bills. Hannah Foslien/Getty Images

But now, Diggs is even more hyped. Wheeled through the entrance to the locker room is a giant delivery of Starburst, one of Diggs' favorite candies.

Similar to how he outsmarts press coverage, Diggs darts off the black leather couch and begins his pursuit to find out if that box is for him (spoiler: it was eventually dropped off by equipment manager Dennis Ryan in front of Anthony Barr's locker.)

"Hey, come sit down so we can finish this!" Thielen yells in Diggs' direction.

Among the many ways they aim to hold each other accountable is simply by how they balance each other out. On game day, neither needs extra motivation to perform at a high level. Diggs finds Thielen actually helps him take it down a notch.

"I'm so hyperactive," Diggs said. "He helps me lock in a little bit more like, 'Hey, one play at a time. Take your time.'"

Over the past two seasons, Diggs and Thielen have reached their own milestones but often point to the other when reasoning why they were able to achieve that success. That's why being considered among -- if not the -- best receiving duo in the NFL is an honor they're grateful for, but one they don't let define them.

They'd rather live by a different rule, the one that's kept them accountable to themselves and each other, and allowed them to get this far: Show, don't tell.

"I think that's why we both have a chip on our shoulder and we play with passion I don't think everybody plays with," Thielen said. "I think that's helped us get to where we are."