Felipe Nasr got the chance to drive a Williams in the second day of testing in Bahrain.
Performance gap between medium and soft tyres drops as track temperatures fall during the evening race.
Felipe Massa made a great start to fight his way into third whilst Valtteri Bottas suffered wheelspin at the start and dropped from third position to fifth.
Top 6 of today's free practice result were claimed by Mercedes-powered teams.
Felipe Nasr: "... it's been a long time since I was in the car here in testing so it took time for me to get back into the F1 mode."
"We are still in the learning process" - Alan Permane, Lotus F1 Team chief engineer.
Felipe Massa: "These extreme temperatures means Malaysia is less like any other circuit we will race at. "
Wolff tried to convince 51-year-old Lowe to leave McLaren.
The team is encouraged by the performance of the car in both short and long runs
Williams last won this race in 1996 and the team hopes to kick off its new partnership with Mercedes-Benz HPP with another strong result.
The agreement, stipulates that each team will devote one day per year exclusively to testing the latest products and developments from Pirelli.
Iconic Martini brand returns to Formula One as title partner of the legendary Williams F1 Team.
Mercedes, McLaren, Williams and Force India - appear to have hit the jackpot with clearly the best turbo V6 'power unit' in F1's new greener era.