Bottas bettered his previous best time from last week by nearly four tenths of a second in 1min 19.310, as defending champions Mercedes AMG had meanwhile reasserted their dominance at the top of the time sheets.
Felipe Massa was surprisingly fastest for Williams on Tuesday, and the Brazilian posted another promising time just over a tenth of a second slower than Bottas in second fastest.
Ferrari's Kimi Raikkonen was nearly a second back in third, but on slower soft tyres compared to the supersoft and ultrasoft compounds used by Bottas and Massa respectively.
In a familiar tale of the first six days of testing, 2005 and 2006 world champion Fernando Alonso endured another frustrating day in the beleaguered McLaren MCL32.
The Spaniard lagged last among the 10 drivers on the track after posting just 27 laps in a series of truncated outings.