Posted by Sabrina B. @gametimegirl

Miami Heat superstar Chris Bosh has a NEW biggest fan … his brand new baby boy … who cheered on his famous dad from his hospital room yesterday … just HOURS after he was born. 

Bosh had a helluva Tuesday … with his wife Adrienne giving birth to little Jackson Bosh around 3 AM … and then having to play in the NBA playoffs against the NY Knicks.

But Bosh made it happen — hopping on a private jet in Florida and arriving over to Madison Square Garden an hour before the game.

With his son decked out in custom Heat gear … Chris scored 9 points in the win over the Knicks … and then hopped BACK on the jet to return to his family … completing a 3,600 mile round trip in less than 24 hours.

Congrats!!

–TMZ