There was nothing to choose between Formula 1's big-hitters as Mercedes and Ferrari led the way in Friday practice ahead of the Chinese GP on Sunday.Lewis Hamilton looked to have set an imposing mark when he leapt out of the blocks and posted the quickest time on the second softest tyre in the morning.By the end of the second session though, it was still the world champion that led the way, but the Scuderia was firmly on his tail with just over a tenth of a second covering the top four drivers.Kimi Raikkonen got the closest finishing just 0.007s behind Hamilton, while Sebastian Vettel set his time slightly earlier than his teammate which was perhaps the reasoning for his one-tenth deficit in fourth.The final member of the quartet was the second Mercedes driver of Valtteri Bottas as he split the two Ferraris in third.The day was characterised by two things, the wind and tyres as drivers struggled to complete a clean lap.Shanghai's international circuit already possesses some of the most technical corners on the F1 calendar and the blustery conditions meant many drivers were seen running off the track with several spinning into gravel traps.One such driver was Max Verstappen as he lost the rear of his Red Bull just as he planted the throttle to start a flying lap exiting the final corner during the morning and almost hitting the barrier.By the end of the day though, the Dutchman would be three-tenths off the ultimate pace set by Hamilton in fifth hinting that a three-team battle is possible should the car run reliably.His teammate Daniel Ricciardo will also hope to join that fight, but a mistake on his best lap left the Australian a full second behind in ninth.In the midfield, the competition is just as strong with five teams all looking capable of fighting for the final top 10 places.Renault and Haas driver Kevin Magnussen were the consistent performers at the head of the pack with McLaren, Force India and Pierre Gasly not far behind, all ready to capitalise.After the drama of Kimi Raikkonen's pit-lane incident last weekend in Bahrain, there was another instance of 'unsafe release' as Stoffel Vandoorne pulled over to the side of the track during the long runs which end the second session.The Belgian, who had also spun off at Turn 10 earlier, reported a loose wheel on his McLaren with the incident under investigation by the stewards.

Towards the back of the grid, Sergey Sirotkin has looked more impressive as he settles in to F1 but it still appears his Williams team will be in a battle with Sauber over the final positions on the grid.

One driver particularly struggling was the Russian's teammate Lance Stroll, as the Canadian spun out through the high-speed Turn 8 and ended the day slowest overall.

Back at the front, the key to success over the next two days is likely going to be who can optimise the Ultrasoft tyre.

Pirelli has been bold by opting to skip the Supersoft and shake up strategies by bringing a compound which should be, in theory, much faster but also less durable.

Traditionally, Mercedes struggle to find as much performance as Ferrari and Red Bull on the softer tyres which explains why they have been more conservative in their selection.

Over a longer stint, performance varied too with some teams struggling to make the purple-striped tyre last, while others, notably Gasly, managed over 20 laps which would certainly be enough for a one-stop strategy.

With temperatures down and other variables to consider too, plenty of twists and turns are to be expected as Hamilton goes in search of his first win of 2018.

The full classification from the second session is available below: