The on-loan Liverpool midfielder’s powerful header in the 40th minute separated the sides in the Bundesliga clash and lifted his team up to sixth.
“When I scored, I was full of emotion and it was a very special moment,” said the 22-year-old, who recently returned from an ankle ligament injury.
“I am very happy to have scored. When the corner came in, I had a feeling I was going to score. It was a very important victory and now we are back in the top six.”
Grujic has made seven appearances for Hertha since joining the club on a season-long loan.