The Team Epsilon driver set a time of 1:50.527 around the new Spanish street circuit, clinching pole in the closing seconds of the session to deny Tristan Gommendy the lead by a tenth of a second.
However, Kubica was not entirely pleased with the performance of his car, stating: "We have to improve the car, it is really oversteering. You risk a lot in qualifying. My last start from pole at Le Mans was not good. Tomorrow I hope there are no mistakes."
Carlin Motorsport's Will Power will line up alongside Kubica after heading the first batch of runners with a time of 1:50.993.
The World Series by Renault cars are split into two separate 15-minute qualifying groups to limit the problem of traffic ruining hot laps. Power was fastest in the first batch of runners.
The average of the five fastest times of each group was outside the new 0.3 per cent window for determining the grid on times alone, required by revised sporting regulations. Therefore all those in Kubica's group will line up on the left-hand side of the grid, and those in Power's slower group will line up on the right.
KTR driver Gommendy will start third ahead of Cram Competition's Eric Salignon.
Both halves of the session were interrupted with red flags. In the first half, Power's teammate Andreas Zuber crashed into a barrier breaking the car's front wing and damaging his nose. The second half of the session was stopped for half an hour for repairs to be carried out to a drain cover on the bridge.
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