Ferrari showed it has the speed to challenge Mercedes in the Chinese Grand Prix, with Kimi Raikkonen and Sebastian Vettel setting the two fastest times in practice on Friday.
Raikkonen had the quickest lap time, a tenth of a second ahead of Vettel. The Mercedes cars were just behind the Ferrari pair, with Nico Rosberg third and lewis Hamilton fourth, both within half a second of Raikkonen.
Vettel said upon arriving in Shanghai that he believed Ferrari's early season technical issues were behind it and the team had made enough progress over the winter to vie for the constructors' championship.
He sounded upbeat on Friday but cautioned against getting too excited. Ferrari also finished 1-2 in the final practice at the Bahrain GP two weeks ago before Hamilton took the pole and Rosberg won the race his second victory of the season.
Ferrari will have another slight advantage in Sunday's race after Hamilton, the world champion and two-time defending champion in Shanghai, received a five-place grid penalty for an early gearbox change.
Red Bull driver Daniel Ricciardo had the fifth fastest time of the afternoon practice session, followed by Toro Rosso teenager Max Verstappen, Force India's Nico Hulkenberg, Toro Rosso's Carlos Sainz, Force India's Sergio Perez, and Williams' Valtteri Bottas.
Mclaren driver Fernando Alonso returned to the track for the first time since his spectacular crash at the Australian GP last month, setting the 11th fastest time.
Alonso's fractured rib ruled him out of the Bahrain GP. He was provisionally cleared to practice on Friday and then given the green light by doctors to race this weekend.
Williams driver Felipe Massa and Renault driver Kevin Magnussen both had tire issues in the morning session that prevented them from setting a time. Massa's left rear tire came off the rim as he was going into Turn 5, causing him to spin across the track in a cloud of white smoke. When he returned a short while later, he had another problem with the same tire and was forced to stop again.