SHANGHAI • Ferrari struck a psychological blow ahead of the Chinese Grand Prix as Kimi Raikkonen and Sebastian Vettel pipped the dominant Mercedes in yesterday's second free practice.
Raikkonen blazed to a fastest lap of 1min 36.896sec, edging Vettel by 0.109sec, as Ferrari bared their teeth after some indifferent form in the season's first two races.
Nico Rosberg, who won in Australia and Bahrain, went third quickest in 1:37.133 after posting the fastest time in the morning, while world champion Lewis Hamilton was fourth in the Shanghai haze.
"They are pushing us very hard," Mercedes chief Toto Wolff said of Ferrari. "You have seen today, its raw performance."
Fernando Alonso, who fractured his ribs after a terrifying crash in the season-opening race, was formally cleared to compete by medics after clocking the 12th-fastest time in the morning. He inched up to 11th in the second session.
"I feel good and missed the car a lot in the last 26 days, I'm really happy to be back," Alonso said.
TOUGH RACE AHEAD
They are pushing us very hard.You have seen today, its raw performance.
TOTO WOLFF, Mercedes boss, on feeling Ferrari breathing down their necks.
"There's still a little bit of pain because my rib has not completely recovered which is normal. But the pain will be manageable in the race."
Ferrari, meanwhile, are managing expectations, even though both their former world champions put in blistering qualifying simulation times on super-soft tyres.
Raikkonen, who finished runner-up to Rosberg in Bahrain two weeks ago, revealed that he was not comfortable on any tyre apart from the super-softs.
"I only used the medium in the morning and it didn't feel very good. But the softs didn't feel very good. The super-soft was the best, but it is too early to say."
The super-soft tyres are the quickest of the three types available for tomorrow's race but also lose performance rapidly.
The Chinese race is heavier on tyres than tracks in Melbourne and Bahrain, where the super-softs have been used previously this season.
Drivers will spend some 80 per cent of the Chinese circuit negotiating turns and high-energy corners and the unpredictable weather in Shanghai could also affect tyre degradation.
Four-time world champion Vettel, third in last month's Australian Grand Prix, also cautioned against over-optimism.
"We had a decent day but it's only Friday so I wouldn't stress or put too much importance on the times today," said the German.
"We can still improve. One lap is good for qualifying but in a race ideally you want to have a lot of good laps in a row."
Mercedes for once did not have things all their own way, with Rosberg's car suffering ignition problems and Hamilton, who has been hit with a five-place grid penalty after a gearbox change, twice spinning off at turn 11.
"Something's up, I keep having this locking into turn 11," complained Hamilton after his second mishap at the hard-braking left turn.
AGENCE FRANCE-PRESSE, REUTERS