The qualifying session at Monza two weeks ago had showed that the Chevrolet cars were the fastest on the long straights.
But instead, the Italian put in two perfect laps, one in Q1 and one in Q2 – with a time of 1:44.358 - to storm to the top of the standings.
Eventually James Nash emerged as the best of the Chevrolet drivers, qualifying in second, only 0.048 seconds behind Tarquini.
"I’m very happy, though a little bit surprised, because the characteristics of this track are similar to Monza’s," Tarquini said. "This result means that the team have done a fantastic job between the two events; they changed something in the engine and this helped us to fill the gap with the Chevrolet cars.
"Tomorrow‘s races will be the first ones for me with the Civic on the dry track. In the winter test I was surprised by how good the car was in race simulation and after today’s pole position I feel very optimistic."
It was a mixed day for Castrol Honda Racing as Tiago Monteiro was eliminated in Q1.
Tom Coronel and James Thompson, who had managed to win a trip to Q2, could not take part after being involved in two different incidents before the end of Q1.