Valtteri Bottas says balance issues made his Mercedes Formula 1 car difficult to drive throughout Friday practice for the Chinese Grand Prix.

Bottas finished over half a second adrift of Mercedes teammate and Friday pacesetter Lewis Hamilton as he struggled with car balance problems in opening practice.

But after switching onto an alternative set-up approach for the afternoon session, the Finn managed to get within 0.033s of the reigning world champion’s best laptime.

“We had some issues with the balance in the morning; the car was quick, but it wasn't easy to drive,” Bottas explained.

"We changed the set-up for FP2 and saw the lap times improve; hopefully we can make another step forward for tomorrow.”

During both sessions the Mercedes duo were split by Ferrari’s Kimi Raikkonen, who got within 0.007s of Hamilton in FP2 as the top four drivers were all split by just 0.108s. Bottas reckons the close battle will continue into qualifying and Sunday’s race.

“Overall, we got some good running and plenty of information, so I'm feeling all set for tomorrow.

“It looks like it will be extremely close again with Ferrari, both in qualifying tomorrow and the race on Sunday.”