The Australian Open champion never faced a break point and used her hard and accurate serve to dispatch Gauff.
Sabalenka appears to have put her past struggles with double faults firmly behind her, not committing a single one against Gauff, while pounding down five aces and winning 87% of her first serves.
Gauff quickly fell 2-0 down in the first set and was unable to match the Belarusian's level despite playing well.
Second seed Sabalenka kept her foot on the gas to dominate the second set despite the California crowd's attempts to urge on the sixth-seeded Gauff.
"I knew you guys wanted to send me home," a smiling Sabalenka told the crowd in an on-court interview after the match.
"Thank you everyone for coming and supporting us, mostly her, but us. The atmosphere was unbelievable. I don't want to leave. I want to stay here as long as I can."
Later on Wednesday, Greek Maria Sakkari fought back from a set down to beat 15th-seeded Czech Petra Kvitova 4-6 7-5 6-1.
Kvitova got off to a flying start, breaking twice to take a 5-2 lead. Sakkari then won back-to-back games, but Kvitova managed to hold serve under pressure to take the first set.
The two-time Wimbledon champion broke in the first game of the second set, but a string of double faults let her opponent back into the match.
Sakkari squared the set at 3-3 before once again taking advantage of Kvitova's shaky serve to force a decider.
Sakkari, last year's runner-up, broke twice in the third set before serving out to win the match in two hours and 15 minutes.
"It is (one of the best comebacks in my career), not only because I was down a set and a break but because she made me play like an amateur in the first set," she said.
"I tried to play as physically as possible, and all I can say is that I need a pedicure now, because my feet are bleeding so badly."
