It was a deep ball that had been completed countless times before. Most of the others just happened to come in May or June, on a practice field in East Rutherford.

But now it was happening on a Sunday in September, at Raymond James Stadium, during the third quarter of a game the Giants trailed by 10 points. Daniel Jones dropped back, slid to his left to avoid pressure, then unloaded a deep ball into the hands of Darius Slayton. The rookie connection may have caught some by surprise, but not the man on the receiving end of the 46-yard gain.

“I’ve been seeing him throw that ball for a minute now,” Slayton said Thursday, referring to the strong throw as “typical DJ.”

That Jones took a big hit right after releasing the ball and was hardly shaken by it didn’t surprise Slayton, either, even if he didn’t know it until he saw the replay later.

“It takes a lot of mental toughness, mental fortitude to focus on still making a great throw while you got 300-pound human beings coming down on you,” Slayton said.

The Giants hope Jones-to-Slayton is a recipe for success for years to come, but the duo took its first step together Sunday in the 32-31 win over the Buccaneers. Jones deservedly grabbed all the attention in his first start, but Slayton quietly put together an impressive debut himself, finishing with three catches for 82 yards and a key block that allowed Evan Engram to go the distance on his 75-yard touchdown.

Jones targeted Slayton five times and all three of the passes he caught went for first downs. His 27 snaps (out of 62) were the third most for a Giants receiver, behind Sterling Shepard (59) and Bennie Fowler (38).

But perhaps most importantly, Slayton was on the field when it mattered most. Jones found Slayton for a 21-yard gain on the second play of the Giants’ game-winning drive late in the fourth quarter. And when Jones ran up the middle for the seven-yard touchdown that will enter Giants lore, Slayton was in the end zone to meet him there after running his route.

“We believe in him,” coach Pat Shurmur said, noting the only thing that held Slayton back was a nagging hamstring injury that forced him to miss most of the preseason and the first two games of the regular season. “It’s good to have him back. He has the ability to go get down the field and make a play. I think that’s part of his charm.”

The Giants lost their only real deep threat when they traded away Odell Beckham Jr., but drafting Slayton with a fifth-round pick a month later reopened that part of the playbook.

Shepard and Golden Tate, who will return from his PED suspension next week, are plenty capable of getting open underneath and catching passes across the middle. But adding Slayton’s vertical threat to the fold should only help them.

“I don’t know how much I helped in just one week, but hopefully as the season goes on, if I’m able to make more plays down the field, hopefully that’ll help open it up for other guys and the run game,” Slayton said.

Offensive coordinator Mike Shula praised Slayton for being a “really good route runner,” especially for a young receiver. Slayton thought that part of his game was underrated coming out of Auburn, but now he will get to test it against cornerbacks who finally have some tape on him.

“Just being able to get out there and play ball, period, is a good feeling,” Slayton said. “Also making plays, it kind of just helps you feel like you belong in this league, that you can compete at this level. Hopefully I’ll be able to carry the momentum through the rest of the season.”