Third place went to Massa’s team mate Valtteri Bottas, while Toro Rosso’s Max Verstappen was fourth, followed by McLaren’s Fernando Alonso. Red Bull’s Daniil Kvyat, Toro Rosso’s Carlos Sainz and McLaren’s Jenson Button completed the timed runners.
Six drivers - Ferrari's Kimi Raikkonen, Lotus's Romain Grosjean and Pastor Maldonado, Sauber's Felipe Nasr and Marussia's Will Stevens and Roberto Merhi - opted not to venture out at all in the tricky conditions.
Vettel was the first man to brave the conditions, his Prancing Horse acting as guinea pig for the rest of the field. The four-time world champion reported standing water between Turns 13 and 2, but suggested the rest of the circuit was merely damp. Even so, it was another half hour before we got our first timed lap on the board, as Alonso stopped the clocks in 2m 05.599s.
Valtteri Bottas, reporting back to Williams after a few untimed runs, described the conditions as "quite tricky," as he oversteered his way around.
Just after the hour, as it became clear that conditions would not improve, Sauber and Marcus Ericsson agreed that going quickly was pointless as they have to push too hard to get temperature into the tyres. Toro Rosso's rookies were not cowed however, with Verstappen and Sainz trading second fastest time in Alonso's wake. Then Verstappen did a 2m 00.806s to go fastest.
As the rain increased the chances of anybody beating that ebbed, but then things improved slightly – enough for home favourite Daniil Kvyat to post 2m 01.418s to go third for Red Bull and Bottas to record 2m 01.443s for fourth for Williams. For Alonso however there was more misery - he was told that his McLaren had a problem that required him to drive slowly back to base.
With the session ticking into the final minutes, Vettel had a moment at Turn 5 and then ran wide at Turn 13, while Bottas undercut Verstappen to go fastest.
That appeared good enough initially, but both Vettel and Massa were on faster laps. The German jumped ahead, but within seconds he had been jumped himself, Massa claiming the honours - and putting Williams on top of a practice session for the first time this year.
Combined with the half-hour reduction in FP1 this morning, the wet conditions in FP2 mean the teams will have an awful lot of work to do in Saturday’s final practice session to prepare for qualifying and the race. Fortunately, the weather forecasts say it will be dry for the rest of the weekend.