Cooper Flagg just sent the Miami Heat to 0-4, and the number that should worry Miami most isn’t the record. It’s that the 19-year-old who did it outplayed Giannis Antetokounmpo on the same night, in the same building.

The Dallas Mavericks won 113-109 at Kaseya Center on Monday, and Flagg’s stat line against the Heat still doesn’t look real on paper: 29 points, 6 rebounds, 11 assists, 5 steals and 2 blocks on 12-for-23 shooting. He’s not a rookie this season — he won Rookie of the Year last year, and this is year two, the season where young stars are supposed to stall out for a little while. Instead, Miami traded for one of the best players alive, signed Klay Thompson in August, and built a roster with real championship hopes. Right now, player development is beating star accumulation, in real time, on their own floor.

Nineteen-year-olds aren’t supposed to do that to two-time MVPs.

At 19 years, 309 days old, Flagg became the first teenager in NBA history to post a game with 25-plus points, 10-plus assists, 5-plus rebounds and 5-plus steals, per the league’s own count. He did all of it returning from a shoulder injury that had him sidelined just one game earlier.

With Miami down two and 31 seconds left, Flagg blocked Andrew Wiggins’ potential go-ahead three, then helped put the game away himself on the other end.

ESPN’s NBA account didn’t need much to make the point.

https://twitter.com/ESPNNBA/status/2114903676510691531

They weren’t wrong. The box score backed up every word of it.

None of this happened because Giannis struggled, either. He had a triple-double of his own in the loss — 29 points, 15 rebounds, 11 assists, his first since arriving in Miami — and the Heat still lost by four. Flagg didn’t beat a tired team riding a hot shooting night. He beat a top-five player on one of that player’s best nights in a Heat uniform, and the final score still said Dallas won.

Miami’s issues go well beyond one rough matchup, too. This is the Heat’s worst start since 2007-08, and it comes one game after Giannis had to foul out against the Hornets. Bam Adebayo has already had to push back on being made the scapegoat for an offense that isn’t working.

Coach Erik Spoelstra tried to sound hopeful about it: “We’ll get there, but I can see and feel how much our guys are wanting to play well, and it’s not happening, so we have to manage that, and show the fortitude until we get a breakthrough.”

Miami built this roster to win a championship this season. Right now, their biggest problem is 19 years old, wears an away jersey, and isn’t finished growing yet.