Huub Stevens' arrival at the Mercedes-Benz Arena has sparked an upturn in form for Stuttgart, who have picked up 11 points from a possible 21 under the Dutchman.
Their latest triumph came at the cost of one of Stevens' former clubs, with Martin Harnik opening the scoring from Daniel Didavi's free-kick 23 minutes in.
Cacau spurned a gilt-edged chance to extend Stuttgart's advantage eight minutes before half-time, but atoned for that miss after the interval when he converted Ibrahima Traore's cross.
The goal was the Germany international's first since September 2012.
Harnik's second put a rampant Stuttgart in control, meaning Adam Szalai's consolation effort counted for little with Schalke now sat four points clear of Bayer Leverkusen, who resumed fourth place with a 4-1 thumping of Nuremberg.
Sascha Lewandowski has now won both games in charge since resuming first-team duties in the wake of Sami Hyypia's sacking to keep Leverkusen's Champions League hopes on track.
Hamburg's 3-1 defeat to Wolfsburg on Saturday gave Nuremberg the chance to jump into the relegation play-off place, but they capitulated in front of their home fans.
Emir Spahic lashed Leverkusen into a 16th-minute lead, but the visitors remained shaky at the back and Marvin Plattenhardt's free-kick from wide deceived everyone to sneak in for an equaliser.
Leverkusen turned the heat up in the second half though and went back ahead through Sebastian Boenisch's deflected effort.
