The Borussia Dortmund defender was left out of Germany's latest World Cup qualifier after making a poor start to the season at club level
Hummels had been held culpable for the Germans' 3-3 draw with Paraguay in August, with Low opting to pick Boateng ahead of him for die Mannschaft's latest World Cup qualifier.
And the trainer's faith was rewarded with Germany's first clean sheet since March, leading him to cite the grounds why Hummels had been relegated from the team.
"Hummels is a very good central defender," began Low to SID. "[But] I've seen him in recent games for Dortmund.
"Maybe he lacks the security. Boateng earned this opportunity because of his performances for Bayern Munich. You cannot always prevent opponent's chances, but it is always up to the whole team.
"The intensity which we attacked Austria with was much higher than recent games. They were forced to play high balls which our defence intercepted easily."
Friday's result in Bavaria ensures Germany maintain their five-point lead over Sweden at the top of Group C ahead of their trip to the Faroe Islands on Tuesday.