Formula One world champion Lewis Hamilton acknowledged it would be difficult to beat Mercedes team-mate Nico Rosberg in Bahrain after being second fastest in practice on Friday.
Hamilton was outpaced by Australian Grand Prix winner Rosberg in both sessions, eventually ending the day 0.241 seconds slower at Bahrain International Circuit.
Despite being the two-time defending champion in Bahrain, Hamilton believes he has his work cut out against Rosberg.
"Nico is always fast here, so it's always a huge challenge to beat him on this track and I haven't got the balance right just yet," he said.
"If I get it right, we shall see but it's always hard.
"Naturally I have to keep trying to dial in the car. I need to find a little bit of time in the final sector, but I lost a bit of time with traffic on the last corner with Sebastian [Vettel], but it was only a tenth, so he [Rosberg] is still faster by a tenth.
"There is some work to do, it's not impossible, but it's going to be hard."
Hamilton added: "Bahrain is always a difficult place to get the right set-up and balance and it's not been a particularly strong circuit for me, so I have to work quite hard to try to get the maximum out of the car. It's a good track for Nico and one of his strongest circuits, so I'm just working at it one step at a time.
"The long-run pace wasn't so bad and I closed the pace a little bit, so I think it's going to be close for sure."