The NBA will stage its first in-season tournament during 2023-24, with the finals to be played in Las Vegas.
Teams will play four group games in November to decide who goes through to the quarter-finals.
The format will then replicate the NCAA’s hugely popular Final Four, with the semi-finals and final being played at the same venue in December.
“What a perfect opportunity for a global league like the NBA,” said commissioner Adam Silver.
“It’s a perfect tournament fit for our game.”
Silver said the new tournament was based on European football club cup competitions, such as the Champions League.
He confirmed details of the tournament on Saturday in Las Vegas, where the off-season Summer League started on Friday.
But the NBA commissioner said: “It takes a little bit of time to establish a new tradition.
“All throughout sports we’re seeing new innovations and now is the time for this in-season tournament. So here we go.”
The new in-season tournament is part of the NBA’s new collective bargaining agreement with the National Basketball Players’ Association, which took effect on 1 July and runs to the end of 2029-30.
How will the in-season tournament work?
Six groups of five teams each, split between the Eastern Conference and Western Conference, were randomly drawn based on last season’s records.
Each team will play two home and two away group games, facing each group rival once.
The group winners and two wildcards – the next-best team overall from each conference – will advance to the quarter-finals, which will be played from 4-5 December.
The tournament will then head to Las Vegas, which hosted NCAA knockout games for the first time in March, for the semi-finals on 7 December, with the championship match two nights later.
All the tournament’s match results will count towards the regular-season standings, apart from the final.
Those teams no longer in the tournament will play regular-season games on the days when the knockout stages are not being played – 6 and 8 December.
Vegas has hosted a Summer League competition annually since 2004, with all 30 teams taking part each year since 2018.
To strengthen basketball’s presence in ‘Sin City’, a three-day fan event called NBA Con was staged for the first time this year to coincide with the start of the off-season tournament.
Which teams will be competing?
In the Western Conference, Group A will consist of the Los Angeles Lakers, Memphis Grizzlies, Phoenix Suns, Utah Jazz and Portland Trail Blazers.
Group B will feature reigning NBA champions the Denver Nuggets, New Orleans Pelicans, Los Angeles Clippers, Dallas Mavericks and Houston Rockets while Group C includes the Golden State Warriors, San Antonio Spurs, Oklahoma City Thunder, Minnesota Timberwolves and Sacramento Kings.
In the Eastern Conference, Group A features the Philadelphia 76ers, Cleveland Cavaliers, Atlanta Hawks, Indiana Pacers and Detroit Pistons with Group B consisting of the Milwaukee Bucks, New York Knicks, Miami Heat, Washington Wizards and Charlotte Hornets.
Group C will feature the Orlando Magic, Chicago Bulls, Boston Celtics, Brooklyn Nets and Toronto Raptors.