Pastor Maldonado finished fastest for Williams during Friday's rain-affected second free practice session for Sunday's German Grand Prix.
The Venezuelan, who was ninth fastest in the morning's opening session, topped the times with a lap of the Hockenheim circuit in one minute 27.476 seconds midway through the session.
A heavy downpour preceded the session and effectively suspended proceedings for 20 minutes as drivers elected not to go out on the track until conditions had improved.
Track times steadily got quicker and Spanish Grand Prix winner Maldonado edged out second-fastest German Nico Rosberg of Mercedes midway through the session seconds before more rain arrived.
Intermittent rain followed and although teams were able to continue testing their cars, the 27-year-old's time stood strong until the end of the session.
Defending drivers' champion German Sebastian Vettel was third fastest for Red Bull followed by Mexican Sergio Perez of Sauber and Frenchman Romain Grosjean of Lotus.
Force India driver German Nico hulkenberg was sixth fastest followed by Australian Daniel Ricciardo of Toro Rosso.
McLaren's Jenson Button, fastest in the morning session, wound up eighth quickest ahead of Australian Mark Webber in the second Red Bull and Finn Kimi Raikkonen in the second Lotus.
Briton Lewis Hamilton was 19th fastest in the other McLaren and Championship leader Spaniard Fernando Alonso wound up 20th.
The session was red-flagged for the final four minutes after 43-year-old Michael Schumacher destroyed the rear end of his Mercedes car during a high-speed crash at the exit of turn 12.
Despite extensive damage to his car, his home fans were relieved to see the seven-times champion walk away unhurt.