Karthikeyan staged an incredible fight back up the order to win race two after having started seventh on the reverse grid at Donington Park Sunday. Earlier in the day, he came second from pole position in race one.
The former Grand Prix driver, who amassed 40 points during the weekend, is fourth in the standings and 21 points behind leader and Super Nova teammate Vittorio Ghirelli, who is on 191 points. Kimiya Sato (180 points) and Sergio Campana (174) go into the Oct 6 season finale in Brno, Czech Republic, as second and third placed drivers with Karthikeyan breathing down their neck.
The Indian said the win in race two was the best out of his four victories this season.
"It is definitely the most satisfying victory of the season to win by 13 seconds after starting seventh. It was amazing," said an elated Karthikeyan.
The triumph didn't come easy though as the former HRT driver was squeezed off track on the opening lap.
"I managed a good start but got squeezed onto the grass. However, I kept it flat and passed Campana. He passed me back on the following lap but hit my front-left so I had some damage to the suspension," said Karthikeyan, recounting the dramatic opening moments of the race.
The Indian was the first driver to make his mandatory pitstop and exited the pitlane near the back of the pack, but once in clean air, he set a searing pace that other drivers, including the race leaders, could not match.
He steadily climbed up the order as the laps ticked past. With six laps to go, he was in fifth position with all the four ahead of him yet to make their stops.
Despite encountering some traffic, Karthikeyan continued to set a slew of fastest laps while the leaders started stopping.
The 36-year-old finally took the lead on the final lap and crossed the line a massive 13 seconds ahead of pole-sitter Meindert Van Buuren, claiming the fastest lap of the race to top off the flawless weekend.
Karthikeyan had extended his pole streak to four in a row Saturday.