"The Ferraris have been quick from the get-go and picked up more pace from there, so it's completely different to what we've seen in Melbourne," said world champion Hamilton.
"We had some issues with the balance of the car, but we made improvements for FP2. At the moment it looks like the Ferraris are ahead, so we have to keep our heads down, keep working, analyse things tonight and try and come back stronger tomorrow.
"I think as we get to qualifying, everything will get a little bit closer, but it is going to be a tough battle."
Ferrari team principal Mattia Binotto supported that view, saying he thought the results of Friday practice were "misleading" and that
he believed Ferrari had been running their engines more aggressively than Mercedes.
Binotto added that he expects a "very tight battle" with Mercedes in qualifying but did say the team were "progressing" after Australia and they were not suffering from the same problems they had there.
https://www.bbc.com/sport/formula1/47753385