The basketball sailed over Kelly Oubre Jr. and landed directly in front of him as he snuck behind the Brooklyn Nets’ hapless defense at Barclays Center on Monday night. The Washington Wizards rookie gathered the ball in stride without a Nets defender in his vicinity and, as the game clock ticked down to zero, smoothly released a 30-foot runner.

The buzzer sounded while the shot began its arc. The left-handed Oubre held his follow-through for a couple seconds until the ball went through the hoop. He then put his left index finger in the air and continued his jog right off the floor to a path behind the basket leading to the visitors’ locker room for halftime of the Wizards’ 120-111 win.

“You saw how I swagged it out a little bit?” he asked.

The 20-year-old rookie was finally getting significant playing time and was taking full advantage of it. It only took a completely meaningless game for the opportunity. In a game with nothing at stake — Washington was eliminated from playoff contention Friday and Brooklyn’s fate was realistically sealed by Thanksgiving — Oubre’s performance was one of the few purposeful developments for the Wizards.

[Podcast: Warriors-Spurs breakdown, plus reader questions]

The long-distance bucket accounted for the final three of Oubre’s 10 first-half points — a total he hadn’t reached in game since Jan. 16 — in 13 minutes. The lanky 6-foot-7 swingman, who saw some rare minutes at power forward, finished the night with 14 points — the second most of his career — on 6-of-10 shooting and six rebounds in 29 minutes for Washington, which sat John Wall (knee), Bradley Beal (pelvis), Markieff Morris (rest) and Nene (rest) for a game between teams that will begin their summer vacations Thursday.

“He got tired, but it’s a situation, as a kid, you learn,” Wizards Coach Randy Wittman said. “You’re in and out of the lineup. You got to stay ready to play. . . . But I thought he came in there and competed.”

Defense was optional most of the night Monday. The Wizards began the game on a 20-0 run before the Nets — playing without their two best players, Brook Lopez and Thaddeus Young — stormed back to take a lead in the second quarter, which concluded with 139 points between the two teams.

Ramon Sessions celebrated his 30th birthday by leading seven Wizards who scored in double figures with 21 points and 12 assists. It was Sessions’s third double-double in four games replacing Wall, who said before the game that he doesn’t know whether he’ll play in Wednesday’s season finale against the Atlanta Hawks at Verizon Center.

But the game’s result was inconsequential; it didn’t even affect draft positioning because neither team is expected to have a first-round pick in June. One of the few elements that mattered for the Wizards was Oubre’s performance.

[Steph Curry is the NBA’s MVP. And it isn’t close.]

In the Wizards’ previous visit to Barclays Center, on the day after Christmas, they completed a four-game winning streak to move to 14-14 despite a deluge of injuries. Role players and players not expected to log many minutes were stepping up. One of them was Oubre. Playing in the building where he was selected 15th overall in last June’s draft, Oubre made the eighth of his nine starts this season and recorded perhaps his best all-around performance of his young career with 12 points, six rebounds and stout defense in 32 minutes.

He started two days later in a loss to the Los Angeles Clippers, which dropped the Wizards to 6-3 in Oubre’s starts, before Otto Porter Jr. returned to the starting lineup. Oubre’s minutes then tapered off. By the end of January, as Washington became whole, Oubre was out of the rotation completely.

“I was feeling like, ‘I’ve showed I can be in this rotation,’ ” Oubre said. “I can hold my own, so we’ll see what happens next. . . . I was like, I should be able to crack the rotation and be able to play and sustain the whole year.”

But Oubre wasn’t pegged to play a significant role this season. The Wizards had veterans on the wing for their expected playoff push, and if it wasn’t for injuries he would’ve been sent to the NBA D-League. This was supposed to be a redshirt year for Oubre, and it ultimately became one outside the stretch from Dec. 14 through Jan. 20 in which he averaged 6.1 points and 3.7 rebounds in 19.3 minutes over 19 games.

[Wizards lament wasted opportunities after their elimination]

“Just his willingness to learn as a draft pick that high that hasn’t been able to play as much [stuck out],” Wizards guard Garrett Temple said. “He was in and out of the lineup, but he was always professional. Getting his work in every day, looking up to guys, asking questions. Being a sponge. It was a successful season in that regard.”

Oubre has a list of areas he plans on working to improve this summer. He wants to get stronger. He wants to become “more of a knockdown shooter.” He wants to tighten up his ballhandling — particularly his right hand.

The limitations didn’t hinder Oubre on Monday. He was left unencumbered and went left to blow by Bojan Bogdanovic for a vicious one-handed dunk while getting fouled. It was another flash of potential, though he missed the free throw.

“I feel like it was a solid year,” Oubre said. “I got a chance to play. I showed everybody in the league that I’m not a bust. I’m ready. I can play in this league. No matter how many minutes I’ve totaled up the whole year, I got a chance to show everybody that I can play in this league and I can help a team win.”