Like Jovic, Belarusian Sabalenka is yet to drop a set at this year’s Australian Open.
She has now reached at least the quarter-finals in 13 consecutive Grand Slam appearances and is two wins away from a fourth successive final in Melbourne.
The champion in 2023 and 2024, she lost last year’s final to American Madison Keys.
The 27-year-old appeared to be cruising towards a comfortable victory against 17th seed Mboko, leading by a set and a double break.
However, she almost let a 4-1 lead slip in the second set and eventually clinched victory in a tie-break.
“She’s an amazing player, it was quite a fight and I’m super happy that I was able to close this match in straight sets,” said Sabalenka.
“The second set was a bit tricky but I’m happy with the level I played and happy to be through.”