Formula 2 rookie Nyck de Vries ended the final pre-season test day in Bahrain on top by just 0.007s over Oliver Rowland.
Just like on Day 1 and 2, most of the representative times were set in the morning.
Prema duo Charles Leclerc and Antonio Fuoco, yesterday's pacesetter Nicholas Latifi and his DAMS teammate Rowland all led during the session, but it was de Vries leading for the final half hour.
His time of 1m40.583s fell just four hundredths short of Latifi's Day 2 benchmark.
The Dutchman narrowly beat Rowland, as well as Honda protege Nobuharu Matsushita (ART) and Latifi, who were all separated by less than a tenth.
Last year's GP3 top three took fifth, sixth and seventh respectively in the order of Fuoco, Alexander Albon (ART) and Leclerc.
Arden duo Norman Nato and Sean Gelael were next, followed by the two Russian Time drivers Artem Markelov and Luca Ghiotto.
De Vries was also fastest in the afternoon, but his time was more than a second slower.
While Johnny Cecotto was a close second, Nato and Nabil Jeffri in third and fourth were a further one and two seconds off the pace.
Day 3 results
|1||Nyck de Vries||Rapax||1:40.583||1:41.880|
|3||Nobuharu Matsushita||ART Grand Prix||1:40.618||1:46.061|
|5||Antonio Fuoco||PREMA Racing||1:40.780||1:45.436|
|6||Alexander Albon||ART Grand Prix||1:40.844||1:45.754|
|7||Charles Leclerc||PREMA Racing||1:40.916||1:46.925|
|8||Norman Nato||Pertamina Arden||1:41.180||1:42.807|
|9||Sean Gelael||Pertamina Arden||1:41.181||1:45.841|
|10||Artem Markelov||RUSSIAN TIME||1:41.197||1:45.111|
|11||Luca Ghiotto||RUSSIAN TIME||1:41.211||1:45.656|
|12||Louis Deletraz||Racing Engineering||1:41.281||1:46.314|
|13||Sergio Sette Camara||MP Motorsport||1:41.329||1:44.042|
|15||Gustav Malja||Racing Engineering||1:41.592||1:46.539|
|16||Ralph Boschung||Campos Racing||1:41.602||1:45.265|
|18||Raoul Hyman||Campos Racing||1:42.359||1:46.072|
|20||Jordan King||MP Motorsport||1:45.862||1:45.007|