Ahead of today's opening session, the air temperature is 19.1 degrees C, while the track temperature is 27.9 degrees. It is bright and sunny, though somewhat windy.

Before a wheel has even turned we know that Sainz will start from the back of the grid on Sunday after taking on a new engine.

However, there is talk that a number of Mercedes-powered drivers, including Hamilton, will follow suit.

While both Red Bull drivers have already taken on new engines, their cars have been seriously updated this weekend, in terms of a fetching Honda tribute livery.

Following last year's issues with grip - and the total lack of it - the entire track surface has been water blasted in a bid to improve things. Furthermore, the tyre compounds are a step softer.

The lights go green and Alonso, Raikkonen, Ricciardo, Ocon and Giovinazzi are among the first out. All three compounds are in use.

"Grip's a lot better than last year," reports Norris.

As Leclerc (softs) sets a benchmark 27.457, Hamilton heads out on softs. The world champion subsequently posts a 27.439.

Sainz sporting a massive aero rake at the rear of the Ferrari.

Verstappen (softs) goes quickest with a 26.991, ahead of Gasly, Ocon, Vettel and Hamilton.

However, moments later Norris posts a 26.516 and Hamilton a 26.043.

Meanwhile, the FIA confirms that Hamilton has taken on a new ICE (internal combustion engine), which means a 10-place grid penalty.

A 25.968 sees Ocon (hards) go top, while, 13 minute into the session, his teammate has yet to appear.

To give you an idea of how much easier the conditions are this year (with softer tyres too) the fastest time so far is already more than 10 seconds quicker than the best FP1 time from last year," reports Pirelli.

Alonso goes sixth with a 26.074 on the mediums as Bottas posts a 25.367 to go second, only to be demoted when his teammate stops the clock at 24.511.

Fitted with a fresh set of softs, Hamilton improves to 24.250 as Verstappen also fits a new set of the red-banded rubber.

The Dutchman improves to 25.055, but remains 0.805s off Hamilton's pace.

A 24.842 sees Bottas go second to make it a Mercedes 1-2.

With 24:00 remaining, all bar Tsunoda are on softs, Hamilton is quickest, ahead of Bottas, Ocon, Leclerc, Verstappen, Sainz, Alonso, Ricciardo, Latifi and Gasly.

Ocon makes use of the run off at Turn 3 after getting it wrong.

Verstappen improves to second with a 24.603, but remains 0.425s off Hamilton's pace.

Moments later Leclerc goes third with a 26.654, as Ferrari continues to show good pace here.

Tsunoda is told to cool down his front right, the call quite urgent.

"Upshifts are very, very bad," reports Russell.

With 9 minutes remaining, Ocon has completed the most laps (23), ahead of Gasly (22), Bottas, Latifi, Stroll and Tsunoda all on 22.

"We're still looking into this in the background," Verstappen is told, though we are not told exactly what "this" is.

A number of drivers switch to mediums, indeed Latifi is on hards.

The session ends. Hamilton is quickest, ahead of Verstappen, Leclerc, Bottas, Sainz, Ocon, Norris, Gasly, Alonso and Perez.

Russell is eleventh, ahead of Ricciardo, Vettel, Giovinazzi, Latifi, Raikkonen, Stroll, Tsunoda, Schumacher and Mazepin.

Check out our Friday gallery from Istanbul, here.