Alonso was comfortably the fastest race driver in Montreal on Friday

World championship leader Fernando Alonso emphasised his determination to take his fourth straight win in Friday practice at the Canadian Grand Prix.

The Renault star was the fastest race driver, just 0.130 seconds behind BMW Sauber test driver Robert Kubica's pace-setting one minute 16.965secs.

Alonso was 0.395secs ahead of the next race driver, McLaren's Kimi Raikkonen.

Alonso's title rival Michael Schumacher was only 15th in the second session, after being fourth in the first.

We were not quick enough and we have to study the data to see how to improve Michael Schumacher

Kubica set an even faster time in the morning - a 1:16.390.

Alonso, who leads Schumacher by 23 points heading into Sunday's race, did not bother to set a time in the first session, preferring to save tyres for qualifying and the race.

Schumacher said he was not happy with Ferrari's performance.

"We were not quick enough and we have to study the data to see how to improve," the German said.

"Obviously the gap separating us from our rivals is a big one, but we know the situation can change rapidly.

I think maybe today Ferrari was playing Fernando Alonso

"It's down to us to work hard as all the changes will be working in our favour."

But Alonso said he thought Ferrari were disguising their true pace.

"They were not 100% today, tomorrow (in qualifying) they will look competitive," said Alonso.

"I think maybe today they were a little too slow, on purpose maybe. I think maybe today Ferrari was playing.

"I think tomorrow for qualifying Ferrari will be one big opponent."

Alonso, who crashed out of last year's Canadian race while leading, said he was determined to end his poor record in North America, with the US GP following on next weekend.

"I never get on the podium here and in Canada and never finish in Indianapolis, these two races have been quite bad for me in the past, so it's time to change it," said Alonso.

"I think this year I have a great opportunity with a fantastic car and I'm really focused on doing a good job.

"The car has been competitive always, we just need a race with no problems, no mistakes and this Sunday will be the opportunity."

Canadian Grand Prix first free practice times:

1. Robert Kubica (Pol) BMW Sauber one minute 16.390 seconds*
2. Fernando Alonso (Spa) Renault 1:17.095
3. Alexander Wurz (Aut) Williams-Cosworth 1:17.337
4. Kimi Raikkonen (Fin) McLaren-Mercedes 1:17.490
5. Anthony Davidson (GB) Honda 1:17.627
6. Giancarlo Fisichella (Ita) Renault 1:17.805
7. M Webber (Aus) Williams-Cosworth 1:17.848
8. Vitantonio Liuzzi (Ita) Toro Rosso-Cosworth 1:18.009
9. Nick Heidfeld (Ger) BMW Sauber 1:18.015
10. Jacques Villeneuve (Can) BMW Sauber 1:18.035
11. Robert Doornbos (Ned) Red Bull-Ferrari 1:18.201
12. Rubens Barrichello (Brz) Honda 1:18.279
13. Jenson Button (GB) Honda 1:18.429
14. Christijan Albers (Ned) MF1-Toyota 1:18.503
15. Michael Schumacher (Ger) Ferrari 1:18.549
16. Ralf Schumacher (Ger) Toyota 1:18.614
17 JP Montoya (Col) McLaren-Mercedes 1:18.761
18. Christian Klien (Aut) Red Bull-Ferrari 1:18.865
19. Jarno Trulli (Ita) Toyota 1:18.868
20. Scott Speed (USA) Toro Rosso-Cosworth 1:18.907
21 Nico Rosberg (Ger) Williams-Cosworth 1:19.048
22. Felipe Massa (Brz) Ferrari 1:19.099
23. Giorgio Mondini (Swi) MF1-Toyota 1:19.138
24. Neel Jani (Swi) Toro Rosso-Cosworth 1:19.258*
25. David Coulthard (GB) Red Bull-Ferrari 1:19.313
26. Takuma Sato (Jpn) Super Aguri-Honda 1:19.624
27. Sakon Yamamoto (Jpn) Super Aguri-Honda 1:20.197
28. Tiago Monteiro (POR) Midland 1:20.262
29. Franck Montagny (Fra) Super Aguri-Honda 1:21.433