Where Rosberg headed Hamilton by 0.065s in FP1, the order was reversed in FP2 with the Briton a mere 0.024s ahead. But more worrying for Mercedes was that where their closest rival, Ferrari’s Fernando Alonso, had been 0.292s down in FP1, now Daniel Ricciardo’s Red Bull was just 0.102s adrift.
Rosberg set the pace on the soft tyre initially, with 1m 19.424s, from Hamilton on 1m 19.757s and Ricciardo on 1m 19.806s.
When the three switched to the supersofts, Ricciardo upped the ante with 1m 18.443s before Rosberg edged ahead with 1m 18.365s. Hamilton then narrowly undercut that, with 1m 18.341s.
Behind them there was a small gap to Kimi Raikkonen on 1m 18.887s for Ferrari and Kevin Magnussen on 1m 18.960s for McLaren.
Felipe Massa confirmed that Williams will be a threat with sixth place on 1m 19.024s, then came McLaren’s Jenson Button on 1m 19.221s, Red Bull’s Sebastian Vettel on 1m 19.248s, Alonso on 1m 19.329s, and Valtteri Bottas on 1m 19.385s - the Finn taking over his Williams from the impressive Susie Wolff.
Adrian Sutil was 11th in the improved Sauber on 1m 19.417s, ahead of Daniil Kvyat on 1m 19.452s for Toro Rosso, Sergio Perez and Nico Hulkenberg in their Force Indias on 1m 19.581s and 1m 19.593s respectively, and Jean-Eric Vergne on 1m 19.760s in the second Toro Rosso.
The closeness of the gaps - six-tenths between the top five drivers and seven between the next ten - may owe more to the shortness of the Hockenheim circuit than to the teams abandoning FRIC suspension. At 4.574 km the track is only slightly longer than the 4.326 km Spielberg circuit in Austria where Williams beat the Silver Arrows in qualifying and got so close to them in the race.
It remains to be seen, however, whether everyone was playing their full hand today, and qualifying will finally reveal the truth of the pecking order.
Pastor Maldonado took 16th place for Lotus with 1m 20.158s ahead of team mate Romain Grosjean on 1m 20.358s and Esteban Gutierrez in his Sauber on 1m 20.504s. Behind them, Jules Bianchi put Marussia back ahead of Caterham with 1m 21.328s to Marcus Ericsson’s 1m 21.870s.
Max Chilton did 1m 21.898s in his MR03, while Kamui Kobayashi was last on 1m 23.728s in what was another troubling session for Caterham.
The Leafield-based team instructed Ericsson to stop his car early in the session, but later the team were able to get it back to the pits and send the Swede out again; team mate Kobayashi, however, did not have that luxury as his CT05 caught fire exiting the Sachs Kurve, bringing his session to a smoky halt. It remains to be seen how badly it was damaged by the flames.