It was just another fall basketball tournament. Desi Rodriguez didn’t treat it any differently, but looking back more than three years later, it was one of the turning points in his life.

It was at the famed Gauchos Gym in The Bronx. Rodriguez was playing well, throwing down dunks similar to those crowd-pleasing jams that now ignite Seton Hall, using his athleticism in the paint to dominate bigger and stronger opponents.

Little did he know at the time who was watching. James Barrett, an assistant coach at Lincoln High School, who went to prep school with Rodriguez’s basketball mentor, Derrick Mack, was impressed. So was Isaiah Whitehead, the Lincoln star and the top-rated player in the city.

“He was just destroying who he was playing against,” Whitehead recalled.

After the game, Barrett, Whitehead and Mack approached Rodriguez.

“How would you like to come to Lincoln?” they asked.

The preeminent basketball program in the city, Lincoln produced Lance Stephenson, Stephon Marbury and Sebastian Telfair. At Frederick Douglass Academy III, his high school in The Bronx, Rodriguez was putting up big numbers, but his team was going unnoticed in the lower third of the PSAL’s three-tier league. He didn’t receive college letters, let alone individual contact. He didn’t need much convincing, and neither did his mother, Dana, who often heard her son needed more exposure.

“I felt he needed that,” she said, wanting him to get out of their crime-ridden neighborhood in the Morrisania section of the The Bronx.

He left FDA III a few days later, joining Whitehead for the next two years, eventually earning a scholarship to Seton Hall.

“It opened a lot of doors,” he said.

These days, it’s hard to imagine where Rodriguez, 19, was three years ago, he has come so far. He arguably is the best player on a Big East team, one with NCAA Tournament aspirations and a 10-2 record entering conference play. Following a quality freshman year, Rodriguez has emerged as a lethal threat, moving from the four spot to the three.

The 6-foot-6 forward’s numbers across the board are up. He is averaging 12.3 points per game (compared to 5.6 a year ago), 4.6 rebounds and 1.7 steals. After making just one 3-pointer last season, he’s averaging 1.3 makes per game from downtown, a credit to his relentless summer, when he took 500 3-pointers a day, rarely leaving campus because he was determined to become a more versatile player.

“He’s made a significant jump. He’s definitely our most consistent player,” Seton Hall coach Kevin Willard said. “If he stays focused and he stays determined, he has an unbelievable ceiling.”

In the Pirates’ biggest win of the year, a come-from-behind victory over perennial NCAA Tournament team Wichita State, Rodriguez led the charge, scoring all 18 of his points in the second half, a mixture of dunks, 3-pointers and drives into the lane. His one-handed alley-oop slam in a win over Troy was the top play on ESPN’s “SportsCenter.”

“It’s hard to believe,” said Rodriguez, the first member of his family to attend college, a broadcasting and communications major with a GPA of 3.3. “I’m just grateful for this opportunity. It’s just working out so good for me. I’ve never been so happy.

“I definitely feel fortunate and I feel lucky at the same time. Just people giving me opportunities to do well in life. I’m happy to have a free education. That’s the most important part, and to play basketball, the sport I love. I feel blessed.”

The move to Lincoln wasn’t an easy transition. Rodriguez wanted to go home that first week. The round-trip commute was three hours. Eventually, he settled in, mostly because of the relationship he developed with Whitehead.

Both quiet and unassuming, they became fast friends, so close Rodriguez began spending a lot of time at Whitehead’s home with his mother, Ericka Rambert, in Coney Island, up to four nights a week. At the time, his brother, Daniel Rodriguez, was in jail, and Whitehead helped fill that void.

“They treated me like family,” Rodriguez said. “I always came back to dinner, woke up to breakfast.”

As a junior at Lincoln, Rodriguez helped the Railsplitters win a city title. Still, by early in his senior year, his recruitment had yet to take off. Whitehead already had committed to Seton Hall by the start of their senior year, and Rodriguez badly wanted to join him. It wasn’t until the prestigious City of Palms Classic in Florida that the Pirates were convinced.

Rodriguez averaged 20 points and 10 rebounds a game against elite competition, thriving in the spotlight FDA III never afforded him. Against Ben Simmons — the projected No. 1 pick in the June 2016 NBA Draft — and national powerhouse Montverde (Fla.) Academy, he had 25 points and eight rebounds. After the tournament, Willard extended him a firm scholarship offer. Shortly thereafter, Rodriguez was headed to the Big East.

“For him to end up at Seton Hall with his best friend, it’s a beautiful thing,” Mack said. “I couldn’t have written the script any better.”

Mack, a teacher’s aide and coach at P.S. 55 Benjamin Franklin — where Rodriguez attended elementary school — remembers Rodriguez as a troubled kid, not a fighter, but someone who would never back down. It would get him into trouble, and Mack could see Rodriguez going down the wrong path in the gang-infested neighborhood.

“Nobody was punking him,” Mack said.

He would see Rodriguez on the playgrounds, and was impressed with his shooting ability. Mack got him into basketball, brought him onto the team, signed him up for summer leagues. He couldn’t get into trouble because he was too busy playing basketball.

“He always had a tournament I could play in,” Rodriguez said.

Rodriguez has lost three friends to gun violence. A number of young men in his neighborhood his age were recently arrested for gang activity. Mack and Rodriguez’s mother made sure that wouldn’t be him.

“That could’ve basically been him if he had not gone the basketball route,” Mack said.

Rodriguez is a celebrity in his old neighborhood, the kid who has made it, even if he is still in college. His mother’s home in the Morris Houses fills up for road games, everyone crowding around the television. At his old middle school, there is a mural of him on the wall. He often gives extra sneakers out to kids, signs autographs, takes photos, offering them the same advice he was given. “Dunkin’ Desi,” they call him.

“When I’m spotted, everybody comes up to me,” Rodriguez said. “It takes me an hour or two to get upstairs.

“I feel like a role model in my neighborhood. It’s a big responsibility.”

Rodriguez sees basketball as a way out, an avenue to a better life, for him and his family. He wants to provide for his mother, a former nurse on disability after fracturing her ankle and suffering from severe knee tendinitis. Forget about the doubters, the people who questioned Seton Hall offering him a scholarship, those who said he wasn’t a high major player.

Sure, he acknowledges, it feels good to prove thus far they were wrong, but his true motivation comes when he returns home, or speaks to his mother on the phone.

“He always says, ‘Mommy, I’m going to get you out of this neighborhood,’ ” Dana Rodriguez said. “Every time he comes to visit, he says, ‘Ma, where do you want to live? We’re going to go somewhere better than this. We’re going to get into a better place.’ ”

“Every time I see my mom,” he said, “she motivates me.”