Hockenheim, Germany: Jenson Button topped the times for McLaren during Friday morning's rain-hit opening practice for Sunday's German Grand Prix.
The 2009 champion, who has been struggling for pace this season, clocked a lap of the Hockenheim track in one minute 16.595 seconds, just under half a second quicker than his McLaren team-mate and fellow Briton Lewis Hamilton,.
Championship leader Fernando Alonso of Ferrari was third quickest followed by home hero Michael Schumacher of Meredes.
Sauber driver Sergio Perez was fifth quickest ahead of Germans Nico Hulkenberg of Force India and Nico Rosberg in the second Mercedes.
Brazilian Felipe Massa was eighth fastest in the other Ferrari followed by the controversial Venezuelan Pastor Maldonado of Willliams and Lotus driver Romain Grosjean, who completed the top ten.
Defending drivers' champion Sebastian Vettel of Red Bull wound up 12th quickest while his team-mate and Silverstone race winner Mark Webber was 20th.