Il Nuovo Postiglione - Alonso quickest in incident-filled final practice for Canadian GP

The 40-year-old Spaniard, a two-time world champion in 2005 and 2006, clocked a best time of one minute and 33.826 seconds on 'intermediate' tyres,

Pierre Gasly was second for Alpha Tauri, just 0.053 seconds adrift, with four-time champion Sebastian Vettel of Aston Martin third, 0.055 seconds off the pace.

For Alonso, it was a scintillating performance in treacherous conditions on the demanding and fast Circuit Gilles Villeneuve.

He will bid for his first pole position since the 2012 German Grand Prix later Saturday in what are expected to be equally difficult weather conditions.

His Alpine team-mate Esteban Ocon was fourth, ahead of Daniel Ricciardo and his McLaren team-mate Lando Norris, George Russell of Mercedes and the Red Bulls of Sergio Perez and world champion and series leader Max Verstappen.

Carlos Sainz was 10th for Ferrari while team-mate Charles Leclerc did not venture out as several drivers had off-track excursions including Verstappen.

Sainz set the pace for much of the session on full wet tyres after others including Kevin Magnussen of Haas, Vettel and Valtteri Bottas of Alfa Romeo clocked the best time.

After heavy overnight rain, the session began in cool and wet conditions, Kevin Magnussen of Haas and Alfa Romeo's Valtteri Bottas venturing out first on full wet tyres.

They were soon followed by the two Ferraris and Mick Schumacher. He did well to control a lurid snap in his Haas as he sought to learn more about the track, on his first visit to Montreal as a driver.

- Leclerc setback -

During the session, it was confirmed Leclerc would start from the back of the grid after Ferrari chose to replace his power unit, a setback to add to his dismay at the FIA's decision to intervene on 'porpoising'.

Leclerc has had two engine failures in his last three races and has used his permitted allocation of engines, meaning he is now likely to suffer more penalties later in the season.

"It is the best decision we could make," said Leclerc, whose team-mate Sainz will also take a new engine, but without a penalty.

Referring to the debate on 'porpoising', he added: "We have worked so hard to get on top of these issues.

"Our improvement has been massive and now all that work. Do we just put it in the bin because there's maybe one team that is struggling more than others?

"It's my view – I obviously understand that it is very bad on the Mercedes, but I think that there are maybe some fixes for this."

Leclerc made clear his sympathy for Hamilton and Russell, adding that it was "very bad" to see them in pain as they climbed out of their cars in Baku.

But, in essence, he agreed with title rival Verstappen that Red Bull and Ferrari have done their own work to resolve their bouncing problems and the phenomenon of 'porpoising' that came with the new 'ground effect' formula this year.

R.Accetta--INP