Inaki Williams kicked and missed at a low cross, and the ball rolled to Mohammed Kudus, who drove it into the net to give Ghana its lead in the 68th minute.
Cho Gue-sung had scored two rapid-fire goals to equalize for South Korea after Ghana had taken a 2-0 lead in the first half.
Ilkay Gundogan sounded somewhere between insistent and relieved. He and his German teammates had spent the days preceding their opening game at the World Cup trapped in a roiling debate about whether Manuel Neuer, the team’s goalkeeper and captain, would or would not be permitted to wear an armband in support of L.