The Brazilian became only the second double-winner of a truly unpredictable season that’s seen eight different winners in the first 10 races.
In the process, the Audi Sport driver also secured his team a consecutive home victory in the German capital after starting the race third on the grid.
Overall, it was an impressive performance from a dominant Di Grassi who looked to be in control for much of the race.
Having overtaken Stoffel Vandoorne during the early stages, the Brazilian hunted down race-leader Sebastien Buemi before opening up a comfortable lead at the front that was barely threatened by the chasing pack.
“It was an amazing race, super tricky but we managed to do it and get the victory at home,” he said after the race.
“We’ve worked so hard, we managed to qualify well and everything went very good.”
Buemi, who started in pole position, managed to hold onto second place after coming under huge pressure in the final laps — it was the Swiss driver’s first podium place of the season.
Meanwhile, championship leader Jean-Eric Vergne worked his way through the field to secure third spot.
The DS Techeetah driver produced a masterclass in overtaking, powering from eighth to take the final podium place.
He almost managed to take second spot but saw his late challenge seen off well by Buemi.
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As has become standard in this season of Formula E, there was plenty of drama in Berlin with some impressive driving on display.
Britain’s Alex Lynn, who had looked in good form in the early stages, was the first man to retire from the race after suffering a mechanical problem.
His car, marooned on the home straight, caused a temporary lull in proceedings but the race quickly continued for an action-packed final few laps.
The teams will now head to Bern, Switzerland, for the 11th race on the calendar. Verne remains top of the standings on 102 points with Di Grassi close behind on 96.