(CNN) -- Germany captain Michael Ballack enjoyed a dream return to the Bundesliga as his Bayer Leverkusen side claimed an impressive 2-0 victory at Borussia Dortmund on Sunday.
Ballack, who rejoined first club Leverkusen during the summer after four years at Chelsea, played his part in a superb team performance as Leverkusen showed they will be one of the teams to watch this season.
Swiss midfielder Tranquillo Barnetta opened the scoring for the visitors in the 19th minute and Brazilian Renato Augusto added a second goal just three minutes later to ensure the three points.
In Sunday's other match, Mainz secured a surprise 2-0 home defeat over Stuttgart thanks to goals from debutant strikers Sami Allagui and Morten Rasmussen.
Tunisian Allagui opened the scoring in the 26th-minute and Danish international Rasmussen -- who joined on loan from Celtic this week -- added the second two minutes after the interval.
With the first round of matches now complete, Hoffenheim lead the table courtesy of Saturday's stunning 4-1 win over Werder Bremen.
Three goals in a bizarre six-minute spell in the first half proved the difference between the sides after Torsten Frings had put Werder ahead from the penalty spot.
Meanwhile, defending champions Bayern Munich got their season off to a perfect start on Friday as Bastian Schweinsteiger's last-gasp goal gave them a 2-1 victory over Wolfsburg.