Lewis Hamilton set the morning pace on the first day of the final test of the pre-season at Barcelona, as McLaren continued to have trouble with its car.
The Mercedes driver set a best time of 1:24.881 early in the morning with medium tyres, and the benchmark remained unbeaten until the lunch break.
The teams' progress was hampered by rain, which hit the track some three hours into the session.
Williams' Felipe Massa was second quickest, albeit nearly a second off the pace, with Red Bull's Daniil Kvyat in third.
Romain Grosjean was fourth fastest for Lotus, but already over two seconds behind Hamilton, with Sauber's Marcus Ericsson completing the top five ahead of Kimi Raikkonen's Ferrari and Carlos Sainz in the Toro Rosso.
McLaren had a torrid start to the test, with Jenson Button managing just seven laps - only one of those timed - as the Honda-powered team continued to struggle ahead of the start of the season.
Red Bull's Kvyat caused the only red flag of the morning when he stopped in the pitlane just as the session was beginning.
Force India did not run as it continued to work on preparing its 2015 car for its debut tomorrow.
|3.||Daniil Kvyat||Red Bull-Renault||1:25.947||+1.066||45|
|7.||Carlos Sainz||Toro Rosso-Renault||1:27.866||+2.985||34|