Flagg became the only 18-year-old player in NBA history to notch 40 points in a game. Naturally, he is also the youngest player in league history to reach that mark. LeBron James, who previously held the record for most points scored at 18, put up 37 points on Dec. 13, 2003, against the Boston Celtics.

Keyonte George scored 37 points -- his second straight 30-plus-point game -- and dished out six assists while leading the Utah Jazz to a 140-133 overtime victory against the Dallas Mavericks on Monday in Salt Lake City.

The NBA schedule on December 15 delivered a busy night filled with close finishes, big performances, and costly mistakes. Some teams stepped up when it mattered most, while others let wins slip away late.

This article was originally published on www.si.com/nba/mavericks/onsi as Dallas Mavericks' Cooper Flagg passes Hall-of-Famer in NBA history against Jazz.

Taking on the Utah Jazz, Flagg topped 40 points for the Mavericks, although Dallas fell 140-133. Still, Flagg's outing was historic; he set a new NBA record for points by an 18-year-old. Here's a look at Flagg's breakout night against the Jazz. MORE: Which teams are in the NBA Cup championship?

There was a lot of hype entering the 2025-26 NBA season around first overall pick Cooper Flagg. MORE: Deandre Ayton’s mom cooks incredible Jamaican holiday meal for Los Angeles Lakers And the former Duke Blue Devil showed exactly why on Monday with a historic display against the Utah Jazz.

Flagg's 42 points tied Mark Aguirre for the most by a rookie in franchise history. Aguirre accomplished the feat in just his 9th game in the NBA against the Golden State Warriors back on November 14th, 1981, which was also a loss for the Mavs.