Christian Klien set the pace at Bahrain on Monday, as testing resumed at the Sakhir circuit following a weekend break.
The BMW Sauber test driver posted a best time of 1:32.544 as his team, as well as their rivals, had a very productive session, trying to make up for the time lost last week due to the bad weather.
"Today was a very productive day," said Klien. "We collected a lot of data and I even did a long run at the end of the session. Again we didn't have a single technical problem, which is very encouraging."
Kimi Raikkonen was second quickest for Ferrari, the Finn working on assessing different set-up configurations and on a comparison of the different types of Bridgestone tyres at the wheel of the F60.
Toyota's Jarno Trulli was the busiest man on track, covering over two grand prix distances in the TF109. The Italian focused on mechanical and aerodynamic set-up along with tyre comparisons.
"We made it through way more than two race distances today - in fact I think this is my personal best for mileage at a test day," said Trulli.
"So I'd say this was a positive and productive day. There were a lot of items to test on a full programme and we got through everything. We made good progress and we were consistently competitive all day long. This has been a good start to our second week here."
Testing in Bahrain continues tomorrow.
Pos Driver Team Time Laps 1. Klien BMW-Sauber (B) 1:32.544 131 2. Raikkonen Ferrari (B) 1:32.804 116 3. Trulli Toyota (B) 1:33.064 141 All Timing Unofficial