In a rematch of their US Open final in September, the two reigning hard-court Grand Slam champions made contrasting starts as Belarusian Sabalenka fired an ace and revved up her forehand to hold before pouncing on two double faults by Gauff to break.
Gauff hit back right away and the pair swapped breaks again but the 19-year-old New York champion continued to teeter on her serve, allowing Sabalenka to settle her nerves after going 6-5 down in a frantic spell to clinch the first set in a tiebreak.
The pair were locked together until 4-4 in the second set as Sabalenka countered Gauff's speed with power and the 25-year-old second seed edged ahead with a decisive break when the teenager hit a shot long before sealing victory with two massive serves.
"I really enjoy playing (Coco) she's an incredible player, win or lose it's great matches," said Sabalenka, who fell in three sets to Gauff in the Flushing Meadows final.
"I really hope in the future we're going to play many more finals. Of course, I hope I win them all," she added with a laugh.
Sabalenka will now set her sights on becoming the first woman to win consecutive Australian Open titles since compatriot Victoria Azarenka in 2012 and 2013.
"I think I was able to focus on myself," she added. "I was thinking she's going to move really well, put all balls back to me and I had to be ready to play an extra shot.
"I was just ready for anything tonight and I think that was the key. And the support, last time I played here I didn't have almost any support."
