Max Verstappen installed himself as the early favourite for this weekend's Canadian Grand Prix after topping both practice sessions on Friday.
The Red Bull driver posted a best time on 1m12.198s in the afternoon in Montreal to lead the Ferrari of Kimi Raikkonen as both men used the Hypersoft tyre to set their best time.
Monaco race winner Daniel Ricciardo had a tricky day after suffering from an asthmatic-sounding Renault engine in the morning, leaving him slightly down on power.
That would then cost him around an hour in the afternoon as the mechanics replaced the wiring loom and other components to try and clear it but eventually, the Australian would complete some flying laps in the last 20 minutes finishing third fastest overall on the pink-striped rubber.
Championship leader Lewis Hamilton remains very much in contention from fourth as his Mercedes team take an alternative approach of focusing mostly on the Ultrasoft compound after their Hypersoft problems in Monaco.
The Briton's best time was almost six-tenths slower than the leading Red Bull but that is a gap which is more than closeable once he too uses the fastest tyre and turns up his engine.
Of the top six drivers, Sebastian Vettel appeared to be the one struggling most as he only completed 19 laps in the morning and only managed five more than that in the second session as Ferrari made setup changes to his car.
With confidence an important factor to a good lap time around the Circuit Gilles Villeneuve, his lack of running may explain the near eight-tenth deficit to the front, but on a weekend where Mercedes could be exposed, the German will need to improve to take advantage.
Haas lead a very tight midfield
On a short circuit with a low downforce configuration, it is to be expected that the always competitive midfield battle will be a little closer.
However, with 10 cars covered by just over half a second, any error by a driver from one of the six teams included could be the difference between Q3 or a Q1 elimination in qualifying.
Initially, it was McLaren and Renault looking strong but by the end of the day, it was Romain Grosjean in the updated Haas who took the prized 'best of the rest' position in seventh.
Force India always go well on power-orientated tracks and so it showed again with Esteban Ocon eighth just ahead of teammate Sergio Perez in ninth, potentially building to a repeat of their notably battle last year.
The opposite can be said for McLaren who normally sit near the bottom of the top speed stats but as always, Fernando Alonso can't be ruled out and the Spaniard took the final top 10 place.
Sauber & Toro Rosso gain from Renault pain
Charles Leclerc has found himself racing against the double world champion he grew up idolising a lot in recent races and the Monegasque was just 0.018s slower in P11 with an impressive lap for Sauber.
Toro Rosso are also hoping for a lift from a newly upgraded Honda engine and it is working with Brendon Hartley 12th in the afternoon after teammate Pierre Gasly had been in the top 10 in the opening practice session.
Their perhaps higher-than-expected positions could be explained by a bad day for Renault as Nico Hulkenberg lost almost all of Practice 1 to a gearbox problem which caused him to stop out on track.
Then, in the afternoon, Carlos Sainz would lose control and hit the wall at Turn 7 causing enough damage to the rear of the car to leave him stranded in the garage for the rest of the session.
Montreal's walls bite back
His would be one of a number of incidents with drivers just pushing the limits a little too far during Friday as Stoffel Vandoorne was another to end his day early after puncturing his right-rear tyre against the barrier exiting Turn 9.
Slowest on the timesheets all day were Williams as their problems continue and they weren't helped by Lance Stroll and Sergey Sirotkin both making contact with concrete in the morning.
Local driver Stroll would be a victim of the 'Wall of Champions' at the final chicane as he biffed the barrier enough to puncture his right-rear, meanwhile his Russian partner would spin approaching Turn 6, reversing into the safety barrier.
A muddled picture remains
Back at the front to conclude and with several interruptions, car issues and traffic interfering during the day, a clear picture is yet to really emerge in Canada.
Red Bull again look very competitive thanks to the Hypersoft tyre and had good speed on the straights but Mercedes also look strong without really revealing their hand thanks to their different tyre approach.
The unknown is Ferrari who many expected to be the fastest but appeared a little lost, at least on Vettel's side.
Typically the Scuderia pick it up on a Saturday though as do Mercedes so it will be fascinating to see if Verstappen and Red Bull can stay ahead.
Full results for second practice can be seen below:
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