While some rivals may have hoped the universal dropping of Front-and-Rear Interconnected suspension (FRIC) systems would hinder Mercedes, the Silver Arrows remained out front as the pecking order stayed largely unchanged.
Behind Rosberg and Hamilton, who recorded 1m 19.131s and 1m 19.196s respectively, Fernando Alonso showed Ferrari's usual Friday pace by locking out third on 1m 19.423s - little more than a quarter of a second behind Rosberg.
Daniel Ricciardo took fourth for Red Bull on 1m 19.697s ahead of a revived Jenson Button on 1m 19.833s for McLaren. Sebastian Vettel, quickest early on, fell back to sixth on 1m 20.097s in the second Red Bull, ahead of Kevin Magnussen on 1m 20.105s. The Dane had a different rear wing to Button on his MP4-29.
Kimi Raikkonen was back in the cockpit after his Silverstone shunt, but lost a significant amount of time early on with a water pump problem. He eventually got out and quickly leapt up the order, eventually securing eighth place on 1m 20.210s to head Toro Rosso's Daniil Kvyat on 1m 20.337s. Adrian Sutil completed the top ten, bullying his Sauber to a 1m 20.505s to round out the top 10.
Felipe Massa finally emerged as Williams' lead runner once some understeer had been dialled out, and his 1m 20.541s lap was just two tenths of a second quicker than Susie Wolff's 1m 20.769s in the sister FW36.
The Scot hit trouble in the opening moments of the session and had to crawl back to the pits with her car stuck in gear, and a repeat of her Silverstone disappointment loomed. The team got her going again though and thereafter she did a very respectable job as she took 15th overall, ahead of fellow Friday tester Giedo van der Garde who lapped his Sauber in 1m 20.782s.
Between Massa and Wolff, Jean-Eric Vergne was 12th in the second Toro Rosso on 1m 20.586s ahead of the Force Indias of Nico Hulkenberg and Sergio Perez on 1m 20.592s and 1m 20.598s respectively.
The gap between Vettel in sixth and van der Garde in 16th was therefore just seven tenths of a second.
The Lotuses were evenly matched, with Romain Grosjean and Pastor Maldonado recording 1m 21.603s and 1m 21.854s respectively, while Kamui Kobayashi put Caterham back ahead of Marussia - the Japanese driver lapping in 1m 22.572s to head Jules Bianchi on 1m 22.982s.
Marcus Ericsson was 21st on 1m 23.256s as Max Chilton wound up last on 1m 22.299s after his Marussia required attention following a smoky installation lap.