The Belarusian world number two proved too powerful for the 12th seed with a 6-3, 6-2 drubbing in 76 minutes to claim her second Grand Slam crown on Rod Laver Arena.
It capped an incredible display of power and poise from Sabalenka over the past fortnight, with the 25-year-old surging to the title without losing a set through her seven matches.
The last time the tournament witnessed a successful women’s title defence was in 2013, when fellow Belarusian Victoria Azarenka achieved the feat.
With her latest exploits, Sabalenka cemented her reputation as one of the game’s most consistent contenders at Grand Slams, reaching at least the semi-finals in her past six majors, making three finals and winning twice.
Zheng saved three set points with a pair of aces and a winner to hold for 3-5, but it was delaying the inevitable as Sabalenka closed out the set on serve in 33 minutes.
Three double faults, including on break point, immediately put Zheng on the back foot on the second set as the pressure took its toll.
And there was no way back as she conceded another break to slump 4-1 behind when Sabalenka perfectly played a drop shot.
Fighting until the end, Zheng saved four championship points before the second seed closed out the match to bank her 14th career title.
Despite the loss, it has been a breakthrough tournament for Zheng, who will move into the world’s top 10 when the new rankings are released next week.
Sabalenka will remain at number two behind Iga Swiatek, who crashed out in the third round.
