Canadian GP: Hamilton leads FP1, Alonso breaks down on return

The Mercedes driver clocked a 1m13.809s on Pirelli's ultrasoft tyres to finish just 0.198 seconds ahead of championship leader Vettel at the Circuit Gilles Villeneuve.

Hamilton's teammate Valtteri Bottas was third quickest, 0.237s off the pace, with Ferrari's Kimi Raikkonen completing the top four a further two tenths back.

It was until the final third of the session that Fernando Alonso - in his first F1 outing since racing at Indianapolis - set his first timed lap, but soon after, he was told by his team to stop and switch the car off immediately.

Alonso came to a stop at the hairpin, launched his headrest from the car and then threw it back into the cockpit.

McLaren later confirmed a loss of hydraulic pressure was the reason behind the stoppage, with the cause still being investigated.

The track was very dusty early on, with Raikkonen spinning on the exit of Turn 7 and Vettel following suit between Turns 1 and 2 - but both continued.

Hamilton had a moment at Turn 6, the three-time world champion losing the rear turning in before catching it while Nico Hulkenberg spin between Turns 6 and 7.

Hamilton set the early pace ahead of Bottas, with Mercedes beginning its programme on the supersofts and Ferrari focusing on the ultrasofts.

When Mercedes switched to the ultrasofts in the second-half of the session, Bottas and Hamilton traded fastest times.

After the first flurry of laps, it was Bottas who held the edge, the Finn 0.127s faster than his team-mate.

But Hamilton, who was told he could find time through Turns 6 and 7 and Turns 8 and 9, hooked together a cleaner lap to sneak ahead by 0.085s.

The laptimes continued to tumble as the track cleaned up, with Vettel slotting into second.

Bottas locked up on entry to the pits, with the team determining that the front-right was too badly flat-spotted to run anymore and therefore ended his session early.

Force India had a strong session, with Sergio Perez fifth and teammate Esteban Ocon sixth, with the top six within one second of each other.

Max Verstappen was the leading Red Bull in seventh, 1.052s off the pace, with Felipe Massa, Daniel Ricciardo and Daniil Kvyat completing the top 10.

Lance Stroll, driving in front of his home crowd, was 12th, 1.2s slower than Williams teammate Massa.

Carlos Sainz's session lasted just a few corners, with the Spaniard pulling off track after the hairpin on his installation lap with smoke coming from the back of his Toro Rosso.

Cla	Driver	Chassis	Engine	Laps	Time	Gap
1	Lewis Hamilton	Mercedes	Mercedes	36	1'13.809
2	Sebastian Vettel	Ferrari	Ferrari	28	1'14.007	0.198
3	Valtteri Bottas	Mercedes	Mercedes	21	1'14.046	0.237
4	Kimi Raikkonen	Ferrari	Ferrari	28	1'14.230	0.421
5	Sergio Perez	Force India	Mercedes	34	1'14.578	0.769
6	Esteban Ocon	Force India	Mercedes	35	1'14.785	0.976
7	Max Verstappen	Red Bull	TAG	19	1'14.861	1.052
8	Felipe Massa	Williams	Mercedes	31	1'15.106	1.297
9	Daniel Ricciardo	Red Bull	TAG	23	1'15.441	1.632
10	Daniil Kvyat	Toro Rosso	Renault	26	1'15.658	1.849
11	Stoffel Vandoorne	McLaren	Honda	29	1'15.943	2.134
12	Kevin Magnussen	Haas	Ferrari	25	1'16.233	2.424
13	Lance Stroll	Williams	Mercedes	36	1'16.313	2.504
14	Romain Grosjean	Haas	Ferrari	18	1'16.345	2.536
15	Nico Hulkenberg	Renault	Renault	27	1'16.473	2.664
16	Fernando Alonso	McLaren	Honda	13	1'16.521	2.712
17	Marcus Ericsson	Sauber	Ferrari	24	1'16.805	2.996
18	Jolyon Palmer	Renault	Renault	26	1'17.004	3.195
19	Pascal Wehrlein	Sauber	Ferrari	28	1'17.606	3.797
20	Carlos Sainz Jr.	Toro Rosso	Renault	1