Mahindra also had a podium on Saturday in the first race when Nick Heidfeld finished third while Rosenqvist endured a no-points finish due to a technical infringement.
In the dramatic race two today, Rosenqvist started from the pole position, dropped to eleventh but fought his way up to finish second.
He then inherited the race win when Abt's Audi was excluded from the results, which gave Mahindra Racing their first victory of the season.
"We haven't really had an idea of what our M4 car is like on a street circuit until now, but this weekend really showed that we have the pace to be very competitive. For sure, we made a few mistakes, but we also got a lot of things right. I struggled with my brake balance through the weekend, and I feel we could have been even better, but for now, Im happy to start the season like this," Rosenqvist said.
"Although we made a few mistakes and let ourselves down a bit, Im happy that the team has picked up where we left off last year. We could have had even better results from the whole weekend, but for now, were happy with the race win, the podium, pole, and fastest lap," Team Principal & CEO Dilbagh Gill said.
The next race is scheduled for January 13 in Marrakesh, Morocco.