Lewis Hamilton admitted his delight with a trouble-free Friday in Korea, where the Mercedes man topped the times in both practice sessions.

The Briton edged out points leader Sebastian Vettel in both sessions at the Yeongam circuit to secure early bragging rights ahead of the race.

Speaking afterwards, the 2008 title winner said he was pleased with the results on track and was confident about the remainder of the weekend, with further improvements to come.

"I was very happy with how the sessions went today and it's the first time I can remember that second practice has really gone well for me," he said. "We haven't changed anything but the day just went smoothly and all the processes with the team worked well.

"I love this track: it was clean from the start, it provides good racing on Sunday afternoon and it just gets harder and harder through the lap. You have the first sector which is good for overtaking, then you get more and more corners coming at you and those final two sectors are all about precision. You need a good downforce package, too, and the car is feeling good.

"We can still make improvements overnight, and I have some things I want to do with the set-up, but it's been a good start for us."

Team-mate Nico Rosberg also enjoyed a solid start to the weekend with the third best time, but admitted to concerns about tyre graining after carrying out a series of longer runs on track.

"The track is really great and the small changes that have been made this year are good improvements, especially the pit exit which is now much better," he said. "Generally it seems that we had a good day but Red Bull is always very hard to beat. We were quite close to them today and I hope this will continue the whole weekend.

"My only concern after the long runs was graining on the front tyres, which is something we need to work on tonight and watch out for. We have brought also some new bits and pieces to Korea, which are working well and leaves me optimistic for a strong result this weekend."