Jenson Button led a McLaren one-two at the end of first practice ahead of Sunday's German Grand Prix.
Button, whose season has fallen off the rails after collecting seven points from the last six races, was quickly out of the traps with a lap of one minute 16.595 seconds. It was a time that was never bettered throughout a session that was hit with the odd rain shower, but failed to affect running too much.
Hamilton, 37 points adrift of championship leader Fernando Alonso in his Ferrari, sneaked within half a second late on to depose the Spaniard from second spot as he finished 0.775secs adrift.
Mercedes' Michael Schumacher led the quintet of Germans on home soil, the seven-times champion 0.787secs down on Button.
Behind Sauber's Sergio Perez in fifth were another two Germans in Force India's Nico Hulkenberg and Nico Rosberg in his Mercedes, both over a second off the pace.
A recently resurgent Felipe Massa was eighth quickest in his Ferrari ahead of Williams' Pastor Maldonado and Lotus' Romain Grosjean who completed the top 10.
Red Bull, who seemingly have again become the team to beat given their pace of late in Valencia and at Silverstone, had Sebastian Vettel down in 12th, 1.744secs down.
As for British Grand Prix winner Mark Webber, the Australian was 20th, 3.527secs adrift, seemingly suggesting he and Vettel were running high-fuel loads.
In between, Williams' reserve Valtteri Bottas was 13th, blotting his previously unblemished copybook - as the Finn has run in the majority of first practice sessions for Bruno Senna this season - with a late spin into the gravel.
Lotus' Kimi Raikkonen spent most of his session testing Lotus' new 'double-DRS' - pioneered by Mercedes - in a bid to find more straightline speed when the system is allowed to be activated. After a number of installation laps, Raikkonen finally raised himself up to 15th late on, but 2.236secs adrift.