Ginobili caught an errant elbow from Mavericks forward Dirk Nowitzki in the third quarter and headed to the locker room leaving a trail of blood.
The Spurs forward returned later in the period and scored 11 of his 15 points in the fourth quarter to push the Spurs to a 94-90 home win and a 2-1 series lead over second-seeded Dallas.
"I had no doubt that he was going to return," Spurs forward Tim Duncan said. "He has a strong nose on him."
Information from The Associated Press was used in this report.