Max Verstappen continued his stunning recent form to comfortably lead the field in first practice for the Canadian Grand Prix.
Following a three-year absence due to the coronavirus pandemic, F1 returned to the Circuit Gilles Villeneuve, with a record crowd expected over the three days.
The reigning champion, who has taken control of the championship after winning four of the last five races, looks set to improve on that record given his early form in FP1.
Red Bull star Verstappen finished with a lap of one minute 15.158s, a quarter-of-a-second clear of Ferrari's Carlos Sainz, who came close to killing a groundhog in the closing stages of the hour-long session.
The animal is renowned at this track for making the odd appearance, and on this occasion, one decided to make a dash from one side of a part of the track to the other, with Sainz coming within inches of running it over.
For once, the Spanish driver had the better of his Ferrari team-mate Charles Leclerc who could only manage the fifth quickest time, with Alpine's Fernando Alonso and the Red Bull of Sergio Perez also ahead of him.
Leclerc, with a new engine, MGU-H and MGU-K in his F1-75 after the blow-up in the last race in Azerbaijan, finished half-a-second back, with Alonso 0.373s down and Perez 0.461s back
All the talk in the build-up to this practice session has centred on the negative health impact on the drivers of the porpoising/bouncing that has dominated the campaign.
The conversation scaled new heights across the weekend of the last race around the bumpy streets of Azeri capital Baku, leading to pain and discomfort for the majority, notably Lewis Hamilton.
In response, and taking the health and safety of the drivers into account, the FIA has issued a new technical directive aimed at alleviating the issue, although the precise nature of the measures in question is still to be determined.
Around the Circuit Gilles Villeneuve, Hamilton and team-mate George Russell again suffered, along with Sainz and Leclerc. For the remainder, it was hard to judge as F1 seemingly shied away from the usual head-bouncing footage.
Hamilton was eighth fastest, 0.719s down, with Russell sixth, 0.664s adrift, with the duo sandwiching Aston Martin's Lance Stroll.
Hamilton and Stroll shared the same time, but with the Canadian ahead by virtue of his lap being ahead of Hamilton.
The second Aston Martin of Sebastian Vettel and Daniel Ricciardo in his McLaren completed the top 10, the latter just over nine-tenths of a second off of Verstappen's leading pace.
The Australian was followed by Pierre Gasly in his AlphaTauri and McLaren team-mate Lando Norris, with Haas driver Kevin Magnussen bringing up the rear, 2.397s down.
Canadian Grand Prix first practice results
1 Max Verstappen [Red Bull] 1m15.158s
2 Carlos Sainz [Ferrari] +0.246s
3 Fernando Alonso [Alpine] +0.373s
4 Sergio Perez [Red Bull] + 0.461s
5 Charles Leclerc [Ferrari] +0.508s
6 George Russell [Mercedes] +0.664s
7 Lance Stroll [Aston Martin] +0.719s
8 Lewis Hamilton [Mercedes] 0.719s
9 Sebastian Vettel [Aston Martin] +0.883s
10. Daniel Ricciardo [McLaren] +0.925s
11. Pierre Gasly [AlphaTauri] +1.007s
12. Lando Norris [McLaren] 1.053s
13. Alexander Albon [Williams] +1.150s
14. Yuki Tsunoda [AlphaTauri] +1.164s
15. Esteban Ocon [Alpine] +1.263s
16. Valtteri Bottas [Alfa Romeo] +1.268s
17. Zhou Guanyu [Alfa Romeo] +1.994s
18. Mick Schumacher [Haas] +2.065s
19. Nicholas Latifi [Williams] +2.083s
20. Kevin Magnussen [Haas] +2.397s