Alonso still on top in practice 2 - Canada

However, the Ferrari was still 0.518 seconds slower than Alonso, whose margin over the competition had been over a second for much of the afternoon.

Mark Webber had used the super-soft tyres to lead the way in the opening half-hour - the Australian staying on top of the timing screens even after the McLarens and Ferraris had emerged, and even extending his advantage to half a second on his second run.

But after 35 minutes, the McLarens resumed the dominant form that they had displayed in the morning, with Alonso beating Webber's time by 0.8 seconds and Hamilton lapping 0.3 seconds slower than his teammate.

Alonso then extended that margin to 1.063 seconds when he tried the super-softs 20 minutes later, and although Hamilton made fractional improvements on his final two runs, he remained 0.757 seconds adrift and was then pushed down to third when Massa produced a 1:17.090 on his last lap.

Kimi Raikkonen took fourth in the second Ferrari, ahead of Nick Heidfeld and Nico Rosberg.

Honda showed improved form with Rubens Barrichello taking seventh. Giancarlo Fisichella, Webber and Takuma Sato completed the top ten.

The afternoon session saw significantly more incident than the morning had done, with many drivers exploring the grass and run-off areas, particularly at the Turn 7/8 chicane.

Heikki Kovalainen had the most dramatic incident, slamming his Renault into the Turn 8 wall in a spectacular shower of sparks. The crippled Renault was retrieved under a local yellow, and Kovalainen would end the session slowest of all.

Robert Kubica's trouble day continued. After missing the whole of the morning with mechanical problems, he had to abandon his first run after spinning and lightly tapping the Turn 8 wall.

His BMW teammate Heidfeld also had a lucky escape, brushing the Turn 4 wall but continuing without notable damage.

Pos  Driver        Team                    Time               Laps
 1.  Alonso        McLaren-Mercedes   (B)  1:16.550            37
 2.  Massa         Ferrari            (B)  1:17.090  + 0.540   34
 3.  Hamilton      McLaren-Mercedes   (B)  1:17.307  + 0.757   36
 4.  Raikkonen     Ferrari            (B)  1:17.515  + 0.965   37
 5.  Heidfeld      BMW Sauber         (B)  1:17.827  + 1.277   42
 6.  Rosberg       Williams-Toyota    (B)  1:17.992  + 1.442   25
 7.  Barrichello   Honda              (B)  1:18.108  + 1.558   38
 8.  Fisichella    Renault            (B)  1:18.130  + 1.580   40
 9.  Webber        Red Bull-Renault   (B)  1:18.181  + 1.631   40
10.  Sato          Super Aguri-Honda  (B)  1:18.309  + 1.759   38
11.  Coulthard     Red Bull-Renault   (B)  1:18.316  + 1.766   40
12.  Kubica        BMW Sauber         (B)  1:18.399  + 1.849   29
13.  Button        Honda              (B)  1:18.474  + 1.924   36
14.  Liuzzi        Toro Rosso-Ferrari (B)  1:18.493  + 1.943   33
15.  Davidson      Super Aguri-Honda  (B)  1:18.545  + 1.995   35
16.  Speed         Toro Rosso-Ferrari (B)  1:18.602  + 2.052   37
17.  Wurz          Williams-Toyota    (B)  1:18.871  + 2.321   25
18.  Trulli        Toyota             (B)  1:18.895  + 2.345   16
19.  R.Schumacher  Toyota             (B)  1:19.331  + 2.781   16
20.  Albers        Spyker-Ferrari     (B)  1:19.453  + 2.903   38
21.  Sutil         Spyker-Ferrari     (B)  1:19.662  + 3.112   25
22.  Kovalainen    Renault            (B)  1:20.519  + 3.969   13