Austria, who lead with 48 points from 20 games at the halfway mark, had Tomas Jun sent off after only 11 minutes for hitting Leonhard Kaufmann on the ear in retaliation following a seemingly innocuous clash between the pair.
Despite the setback, Philipp Hosiner fired the hosts ahead four minutes after halftime with his 21st goal of the season and Markus Suttner and Marko Stankovic were also on target after Rubin Okotie briefly brought Graz back on level terms.
Defending champions and second-placed Red Bull Salzburg (41 points) thumped hapless SV Mattersburg 7-0 on Saturday with Senegalese Sadio Mane scoring a hat-trick.
Georg Teigl, Valon Berisha, Stefan Hierlaender and Jonathan Soriano, from a penalty, shared the other goals in front of less than 4,000 fans.
Second place is disappointing for Salzburg who, according to the website Transfermarkt, spent around 16 million euros ($21.05 million) on new signings in the close season, more than the other nine teams combined.
Third-placed Rapid Vienna, who have won a record 32 titles, dropped three points behind Salzburg after a shock 1-0 reverse at Wiener Neustadt. (Writing by Brian Homewood in Berne; Editing by Toby Davis)
- Sports & Recreation
- Red Bull Salzburg
- Marko Stankovic
- Markus Suttner