Khassenova got the better of a tight opening round and she managed to keep her nose in front at the conclusion of the second.
However, Araujo stepped up a gear in the third round, finding range with her right hand to turn the scores 10-9 in her favour.
The Brazilian continued on the front foot in the final round as the Kazakh was struggling to cope with her pressure.
Khassenova was given two points when Araujo was warned for hitting after the referee had called break.
That forced Araujo to pour forward as she sought to make up for her deduction. She was all over the Kazakh and the referee had to intervene and issue a count.
Araujo's penalty did not come back to haunt her as the judges awarded her a 16-14 verdict.