Title holders Borussia Dortmund had started proceedings with an impressive 3-1 win over Hamburg on Friday thanks to two goals from Germany's rising stars Kevin Grosskreutz and Mario Götze.
But Stuttgart also picked up three points and Cacau, who will be back at Stuttgart's Mercedes Benz Arena on Wednesday when Germany face Brazil, opened the scoring with a 37th-minute header.
The hosts added a second against last season's Champions League semi-finalists when Austria striker Martin Harnik scored with a 56th-minute header.
Striker Shinji Okazaki, who has been named in the Japan squad to face South Korea on Wednesday, made sure of the three points with a superb strike on 89 minutes to make his side joint early league leaders.
"It's nice that we could contribute to this festival of football," beamed Stuttgart coach Bruno Labbadia. "That was a very good day for us, but all that glitters isn't gold: we were still lacking a bit of calm."
Hanover 96, who face Sevilla in a Europa League play-off on August 18, were also winners with a 2-1 victory over Hoffenheim.
Ex-Germany striker Jan Schlaudraff put Hanover ahead when he slotted home a free-kick on 15 minutes, only for Hoffenheim to equalise three minutes later when midfielder Sejad Salihovic converted a penalty.
When Schlaudraff was fouled in the area on 30 minutes, Norway striker Mohammed Abdellaoue stepped up to secure the three points for Hanover.
Having spent last season flirting with relegation, Bremen got their season off to a flying start with a 2-0 home win over Kaiserslautern as Sweden striker Markus Rosenberg netted twice in the second half.
Patrick Helmes scored twice as 2009 champions Wolfsburg won 2-0 at Cologne as coach Felix Magath named midfielder Christian Träsch as skipper after stripping Marcel Schäfer of the captaincy.
Schäfer had the final say as his late header sealed the three points before Helmes scored his second in added time.
Striker Sascha Mölders scored with two headers as newly-promoted Augsburg earned a 2-2 draw at home to Freiburg.
Hertha Berlin, back in the Bundesliga after winning the second division last season, were beaten 1-0 at Berlin's Olympic Stadium on Saturday nigh after Nuremberg's 22-year-old Czech Republic striker Tomas Pekhart netted the winner.
Bayern Munich open their season on Sunday at home to Borussia Mönchengladbach while Bayer Leverkusen are at Mainz.