Teams largely focused on setting their cars up to optimise balance and performance without FRIC suspension systems, the loss of which is widely anticipated to have more of an effect here than it did at Hockenheim last weekend.
Mercedes' dominance was underlined by the fact that Hamilton, who lapped in 1m 25.814s to Rosberg's 1m 25.997s, finished more than a second clear of the rest of the field - with one exception as Ferrari's Kimi Raikkonen set the third fastest time, a 1m 26.421s.
That allowed him to head team mate Fernando Alonso, the Spaniard more than four tenths of a second down the road on 1m 26.872s.
Sebastian Vettel took fifth for Red Bull on 1m 27.220s, as Kevin Magnussen continued McLaren's upward trend with 1m 27.357s. Jean-Eric Vergne also had a good session with seventh best time of 1m 26.683s for Toro Rosso, to lead Daniel Ricciardo on 1m 27.782s in the second Red Bull, McLaren's Jenson Button on 1m 27.804s, Williams' Felipe Massa on 1m 27.960s and Sauber's Esteban Gutierrez on 1m 27.967s.
Nico Hulkenberg was Force India's highest representative in 12th with 1m 28.101s ahead of Toro Rosso's Daniil Kvyat on 1m 28.208s. Lotus's Pastor Maldonado was next on 1m 28.266s, fractions ahead of Williams' Valtteri Bottas on 1m 28.330s, Sergio Perez in the second Force India on 1m 28.376s and Romain Grosjean in the second Lotus on 1m 28.593s.
Adrian Sutil took 18th for Sauber on 1m 29.025s, as Kamui Kobayashi headed Caterham team mate Marcus Ericsson, 1m 30.363s to 1m 30.892s. Max Chilton lost almost the entire session when an oil leak on his Marussia resulted in a fire as he came into the pits following his opening installation lap, but following a gearbox change he got going in the final minutes and recorded a late 1m 31.004s, which lifted him above team mate Jules Bianchi on 1m 31.248s.
While Chilton's was the only major incident, a litany of drivers suffered minor on-track moments - Kobayashi, Ericsson and Sutil even spinning - as grip remained at a premium throughout the 90 minutes. However, the circuit did ramp up as the session went on and rubber was laid down on the racing line, so we can expect much quicker times in FP2 when the teams will also used the yellow-marked soft tyres for the first time.