Lewis Hamilton has identified the optimising of tyre strategy as the key to success at the German Grand Prix with degradation high on Friday.

This weekend, Pirelli has brought the Ultrasoft, Soft and Medium compounds, skipping the Supersoft, but temperatures are higher than expected at Hockenheim with the thermometer passing 30 degrees in Practice 2.

During the race simulation, the world champion had to pit earlier than expected as the purple-striped tyre simply ran out of grip and that is concerning the Briton with little to choose between the top three teams.

"It is very close," Hamilton admitted, having been beaten by a Red Bull by a matter of thousandths in both sessions and with Ferrari right behind.

"There's lots of work to do tonight. We've been working on our starts, making sure to get a better understanding of the tyres and tyre temperatures and trying to be as perfect as we can in that area.

"Both Ferrari and Red Bull were very quick today and I think it will be very similar tomorrow and on Sunday."

With conditions expected to be only a touch cooler in the race, the key decisions are likely to be which tyre to start the race on and whether to commit to a two-stop strategy.

"The Ultrasoft is really on the limit. It's got good grip to start but needs to be driven ever so gently to keep it from blistering," said chief engineer Andrew Shovlin.

"The Soft and Medium are a bit easier to lean on which may mean that we see a range of strategies on Sunday, which should lead to an interesting race."