World champion Lewis Hamilton topped the timesheets for Mercedes in both practice sessions of the Australian Grand Prix Friday but the waterlogged conditions put a dampener on Formula One's season opener. With intermittent showers blighting the day, the teams head into the race weekend short of set-up work and lacking valuable data on their tires, meaning qualifying could be a lottery. Hamilton, bidding for a third successive title with Mercedes, posted a lap of one minute 29.725 seconds in the opening session, over four-tenths of a second quicker than Red Bull's Daniil Kvyat. But the Briton could manage only 1:38.841 in the rain-delayed second, with the track too greasy to go anywhere near full throttle. He was nearly half a second faster than Force India's Nico Hulkenberg, with Ferrari's former world champion Kimi Raikkonen third quickest in the second session. Hamilton's teammate Nico Rosberg, who won the final three races of last season, had a day to forget. After posting the sixth fastest lap in the opening session, he skidded at turn six in the later practice and damaged his front wing in a collision with the barrier. The German rolled slowly around the track for a few moments before being called to stop, as Mercedes motorsport boss Toto Wolff glared at a television screen in the garage. Red Bull had a better day, with Kvyat's Australian teammate Daniel Ricciardo third behind the Russian in the initial run and fourth-quickest in the later session. Four-time champion Sebastian Vettel, tipped to threaten Hamilton's ambitions of a fourth title overall, was eighth quickest in the second session after failing to post a time in the first as gusty winds buffeted the street circuit. His teammate Raikkonen locked up and skidded at a turn in FP1 to post one of the slowest times of the session. Toro Rosso's Carlos Sainz struggled with a reliability problem early and was unable to post a lap time in the early session but returned to record the fifth fastest in FP2. Seven drivers, including both Williams drivers Felipe Massa and Valtteri Bottas, did not trouble the timers in FP2, with teams seeing little value in testing the car in the wet. New team Haas, the first US-owned F1 outfit in 30 years, had a cautious debut with French driver Romain Grosjean and Esteban Gutierrez posting slow times in both sessions.
