Shanghai: Kimi Raikkonen set the pace ahead of Sebastian Vettel in Friday practice for the Formula One Chinese Grand Prix as the Ferrari pair dislodged the dominant Mercedes duo.
The Finn, a former winner for Ferrari in China, jumped to the top of the order with a one minute 36.896 second lap in Friday's second practice session, beating German team mate Vettel by a margin of 0.109 seconds.
Championship leader Nico Rosberg was third for Mercedes, 0.237 seconds off Raikkonen's benchmark.
Rosberg's team mate and reigning world champion Lewis Hamilton, who heads into Saturday's qualifying session with a five-place grid penalty for a change of gearbox, was fourth, 0.433 seconds adrift.
Rosberg had set the fastest time ahead of Hamilton in Friday morning's interrupted opening session in which the Ferrari duo were only third and fifth.
But the Maranello-based squad turned the tables on their German rivals in the afternoon with their runs on the fastest, red-walled, super-soft compound tyre.
Friday afternoon's practice session was only the second time this season that a Mercedes has not ended a session on top.
The German team has won 34 of the last 40 races and started the last eight on pole.
Rosberg, who leads the standings by 17 points from Hamilton, heads into Sunday's race gunning for a sixth-straight win.
The Briton, meanwhile, is aiming to complete a hat-trick of Chinese Grand Prix victories, even if the highest he can start the race from is sixth.
Red Bull's Daniel Ricciardo ended the day fifth, the Australian, fourth in the morning, setting a time 1.247 seconds adrift.
McLaren driver Fernando Alonso, cleared by doctors to compete in Sunday's race after a final round of medical tests following the morning session, was eleventh.
The Spaniard, forced to miss the last race in Bahrain due to injuries sustained in an accident last month in Australia, completed a total of 42 laps over the entire day.
Friday afternoon's running was uneventful compared to the morning's action.
The opening 90-minutes were headlined by two red-flag stoppages as Williams driver Felipe Massa and Renault's Kevin Magnussen both suffered high-speed left-rear tyre failures while running on the soft-compound rubber.
Following an investigation, the sport's tyre supplier Pirelli confirmed none of the failures were tyre-related with a separate technical issue responsible.
The Mercedes pair also reported problems in the morning.
Rosberg limped home near the end of the session with engine issues while Hamilton, struggling with "locking" problems, spun twice at turn 11.
Manageable pain
Fernando Alonso, who fractured his ribs in an accident in last month's season-opener in Australia, admitted to feeling "a little bit of pain" on his return to track action on the opening day of practice for Sunday's Chinese Grand Prix.
Alonso, who sat out the last race in Bahrain on doctors' orders, was cleared to drive in Friday's opening session following a medical test at the Shanghai circuit on Thursday.
He was subsequently cleared to participate for the rest of the weekend after another round of tests following that session.
"I felt good," Alonso told reporters of his first day back.
"A little bit of pain, no surprises there, the rib is still a little bit fractured so that's normal.
"But this is manageable, the pain," he said
Alonso's accident in the March 20 season-opener in Melbourne, in which his McLaren barrel-rolled through the air before coming to rest upside down against a barrier in a mangled heap, left him with fractured ribs and the risk of a collapsed lung.
The Spaniard, twice a winner in China and one of only two drivers to have finished every Chinese Grand Prix since the race appeared on the calendar, had told reporters on Thursday that he had resumed his normal training routine and felt 100 percent physically ready to race.
But the violent forces a driver is subject to in a Formula One had made him feel his injuries.
"It's a Formula One car, so it's quite stiff," the double world champion said.
"Every bump you feel it, every kerb you feel it and that's quite a worse thing but I'm happy and I'm ready to race."
Despite the pain, Alonso ended the day eleventh fastest, a tenth of a second quicker than team-mate Jenson Button, with a total of 42 laps on the board.
He is not required to undergo any fu- Reuters