The hour-long session began with drivers venturing out on wet and intermediate tyres, but despite dark clouds overhead, conditions continually improved with all of the quick times coming right at the very end when the drivers switched to soft tyres.
Rosberg’s best lap of 1m 32.092s on the yellow-marked rubber was the fastest of the weekend thus far, but the fact that Daniel Ricciardo was within three tenths of a second with 1m 32.394s bears out Red Bull’s belief that they can be very competitive here on a track that favours excellent handling as much as horsepower.
Sebastian Vettel was again Ferrari’s faster runner with 1m 32.731s, but the German was disappointed that the team had lost ground to Mercedes since FP2. Max Verstappen was also unhappy in fourth, struggling to 1m 32.784s in a car that he said didn’t handle the way he wanted it to.
Kimi Raikkonen hit traffic on his best lap and ended up fifth, 0.9s back from Rosberg’s marker, with Felipe Massa taking sixth for Williams ahead of the second Silver Arrow of Lewis Hamilton, who spoiled his best effort with a mistake at Degner.
There were big smiles at Renault, where Jolyon Palmer had his best run of the season together with team mate Kevin Magnussen; they were eighth and ninth with exactly the same lap time: 1m 33.639s.
Rounding out the top 10 was Nico Hulkenberg on 1m 33.646s for Force India.
Esteban Gutierrez, 12th for Haas behind Fernando Alonso’s McLaren, provided the most spectacular moment of the session when he spun early on at Turn 5, while mechanical problems left Carlos Sainz’s Toro Rosso down in 22nd place.
The scene appears set for one of the closest qualifying sessions of the season, with both Red Bull drivers fancying their chances of getting up there with the Mercedes duo, provided the set-up of the RB12s can be honed a little further.