Ocean Racing Technology started its Istanbul weekend in fine form by filling the top two spots in Friday morning's free practice session, with Alvaro Parente leading team-mate Karun Chandhok by half a second.
The Portuguese driver set his best lap, a 1min 35.347secs effort, with ten minutes remaining, but yellow flags late in the session meant his competitors were handicapped when it came to trying to match a time that was fully half a second faster than the corresponding lap from last year's free practice session.
Behind Chandhok, championship leader Romain Grosjean was a tenth further adrift in third spot, with Alberto Valerio and Luca Filippi completing an unusual top five.
The session, which took place in blazing sunshine, opened with a competition for the top spot between Valerio, Filippi and Jérôme d'Ambrosio, with the Italian looking to have things under control after Dani Clos spun off at the turn eight complex but remained in his car, causing a yellow flag period for the next ten minutes.
Parente, however, was the first to use fresh rubber once the track cleared, setting a time which was to prove untouchable after Diego Nunes found the barriers at turn four and Grosjean narrowly avoided a stationary Edoardo Mortara in the gravel trap one corner earlier.
Behind sixth-placed Andi Zuber - a winner at Istanbul Park the first time GP2 visited - Lucas di Grassi went some way to providing encouragement for Racing Engineering by claiming seventh spot, with Roldan Rodriguez, Mortara and d'Ambrosio rounding out the top ten.
Further back, ART came down from its Monaco high with something of a bump, with Nico Hulkenberg and spring race winner Pastor Maldonado languishing in 18th and 23rd respectively.