Italian GP: Hamilton leads dominant Mercedes 1-2 in FP1

Hamilton clocked a 1m21.537s on the supersoft Pirelli tyres to finish 0.435 seconds clear of Bottas, with Ferrari's championship leader Sebastian Vettel 1.115s off the pace in third.

With the threat of rain looming, drivers headed out early in FP1 in order to maximise the dry but cool conditions.

Bottas led the way after the opening half an hour, the Finn clocking a 1m22.086s on the soft tyres.

Mercedes then switched to the supersofts, with Hamilton jumping to the top of the timesheets with a 1m21.868s.

The three-time world champion completed a flurry of laps on that rubber, improving to a 1m21.729s and then a 1m21.537s before pitting.

Light rain eventually came with around 15 minutes of the session to go, with race control reporting the track was slippery in sector two, and everyone retreated back to the pits.

The Ferraris then headed out on supersofts, completing a practice starts at the end of the pitlane, before coasting around and returning to the pits.

The rain then eased, allowing a flurry of laps in the final minutes of the session.

Kimi Raikkonen ended the session fourth quickest, a fraction behind teammate Vettel, with Red Bull's Daniel Ricciardo and Max Verstappen a tenth further back in fifth and sixth respectively.

Ricciardo and Verstappen are set for a tough weekend after Red Bull chose to change Renault engine components ahead of the session, meaning they will take 20- and 15-place grid penalties respectively.

Sergio Perez pipped Force India teammate Esteban Ocon to seventh while Stoffel Vandoorne was the highest placed McLaren in ninth, with teammate Fernando Alonso 15th.

Honda fitted an upgraded power unit, known as 'spec 3.7', to Alonso's car for first practice, sparking a 35-place grid penalty for Sunday's race.

The Spaniard then ended the session early so Honda could switch back to an older spec unit - the one Alonso raced at Spa - for the remainder of the weekend.

Honda wanted to use the session to test performance, but save mileage on the engine for Singapore, as it is a track where it feels a good result is possible.

Felipe Massa completed the top 10, two seconds off the pace, but nearly half a second quicker than Williams teammate Lance Stroll.

With rain expected, Haas changed plans and stood down Ferrari junior Antonio Giovinazzi to allow Kevin Magnussen to get running in dry conditions.

It is expected Giovinazzi will get an opportunity to drive in FP1 in Singapore instead.

Cla	Driver	Chassis	Engine	Laps	Time	Gap
1	Lewis Hamilton	Mercedes	Mercedes	28	1'21.537
2	Valtteri Bottas	Mercedes	Mercedes	31	1'21.972	0.435
3	Sebastian Vettel	Ferrari	Ferrari	24	1'22.652	1.115
4	Kimi Raikkonen	Ferrari	Ferrari	28	1'22.689	1.152
5	Daniel Ricciardo	Red Bull	TAG	28	1'22.742	1.205
6	Max Verstappen	Red Bull	TAG	23	1'22.749	1.212
7	Sergio Perez	Force India	Mercedes	36	1'23.317	1.780
8	Esteban Ocon	Force India	Mercedes	34	1'23.400	1.863
9	Stoffel Vandoorne	McLaren	Honda	24	1'23.465	1.928
10	Felipe Massa	Williams	Mercedes	37	1'23.561	2.024
11	Carlos Sainz Jr.	Toro Rosso	Renault	22	1'23.680	2.143
12	Kevin Magnussen	Haas	Ferrari	22	1'23.973	2.436
13	Lance Stroll	Williams	Mercedes	30	1'23.991	2.454
14	Daniil Kvyat	Toro Rosso	Renault	27	1'24.012	2.475
15	Fernando Alonso	McLaren	Honda	17	1'24.015	2.478
16	Romain Grosjean	Haas	Ferrari	22	1'24.079	2.542
17	Nico Hulkenberg	Renault	Renault	17	1'24.542	3.005
18	Jolyon Palmer	Renault	Renault	21	1'25.166	3.629
19	Pascal Wehrlein	Sauber	Ferrari	26	1'25.223	3.686
20	Marcus Ericsson	Sauber	Ferrari	17	1'25.687	4.150