The Greek Freak was nothing short of insane on the court during Game 6 on Tuesday ... earning 50 points, 13 rebounds, and 5 blocks. He also went 17-19 from the charity stripe.

The Suns kept it a close game -- the final was 105 to 98 ... but the Greek Freak and Co. proved to be too much for PHX.

The Deer District -- the fan zone outside Fiserv Forum in Milwaukee -- went absolutely insane as their beloved team won it all ... jumping up and down and chanting for the new champs.

The win all but certainly cements Giannis' spot in the Pro Basketball Hall of Fame -- the 2-time regular season MVP scored over 40 points in 3 of the 6 games in the series.

Giannis finished with an average of 35.2 points, 13.2 rebounds, 5 assists and shot 62% from the field on the series.

Of course, with those kind of numbers, Giannis was the obvious choice for Finals MVP -- the first of his career.

It's a devastating loss for Suns superstar guard Chris Paul ... who was just 2 games away from winning his first ring.

The celebration is just getting started in Milwaukee ... so be sure to check back for all the (probably) drunken debauchery in the morning.