Ferrari showed it has the speed to challenge Mercedes at this weekend's Chinese Grand Prix, with Kimi Raikkonen and Sebastian Vettel setting the two fastest times in Friday's practice sessions.
Raikkonen had the quickest lap time at 1 minute, 36.896, 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's time.
Ferrari demonstrated in the opening two races of the Formula One season that it had the race pace, if not the qualifying speed, to compete with Mercedes, but had suffered engine failures in both races.
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 this year.
He sounded upbeat after Friday's practice, but cautioned against getting too excited. Ferrari also finished 1-2 in the final practice at the Bahrain Grand Prix two weeks ago before Hamilton took the pole and Rosberg won the race — his second victory of the season.
"Friday's not that important in terms of position, it's more in terms of feel," Vettel said. "And the feel was OK, but OK is not good. I think we can still improve, especially the balance of the car."
Ferrari team principal Maurizio Arrivabene also downplayed his team's performance, saying Mercedes was still the team to beat.
"I can say that the Mercedes team of this year is the strongest one in the last 10 years," Arrivabene said. "To win against them, you have to work and be better than them."
Red Bull driver Daniel Ricciardo had the fifth-fastest time of the 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 Grand Prix last month, setting the 11th-fastest time.
Alonso was ruled out of the Bahrain Grand Prix as he continued to recover from a fractured rib, but was provisionally cleared to take part in Friday's practice and then later given the green light by doctors to race for the remainder of the weekend.
The morning practice session proved frustrating for Williams driver Felipe Massa and Renault driver Kevin Magnussen, both of whom experienced tire issues 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 and come to a stop on the shoulder. When he returned a short while later, he had another problem with the same tire and was forced to stop again.
Magnussen's left rear tire blew out on the back straight, bringing the red flag out as debris was cleared from the track and halting practice for 20 minutes.
Massa returned for the afternoon session, but Magnussen's car remained in the garage while his team made repairs.