The Borussia Dortmund defender headed in his side's second goal shortly after the half-hour in Salvador as Germany took a firm grip on Group G.
However, the 25-year-old's day turned sour when he was forced to limp off 17 minutes from time with a thigh problem, to be replaced by Shkodran Mustafi.
Hummels calmed fears over the severity of the injury, and does not expect it to keep him out of the tournament ahead of Germany's next fixture against Ghana on Saturday.
"The injury doesn't feel like something which would end my World Cup," he told Sport1.
"Maybe it will cost me one game, or maybe none at all.
"It looked worse than it is.
"I do have my thigh heavily wrapped, but it's going to be fine. It could have been worse."
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