Mercedes Formula 1 driver Lewis Hamilton has described his Canadian Grand Prix practice crash as an "innocent mistake", that left him feeling like he was "in the headmaster's office".
Hamilton, who had set the pace in the opening Friday practice ahead of team-mate Valtteri Bottas, lost control on the exit of the Turn 8/9 chicane while on an early medium tyre run.
He slid off into the outside wall, making contact with his right-rear tyre - and while he then successfully brought his W10 back to the pits despite the damage, Mercedes was forced to change the rear suspension and he did not rejoin for the rest of the session.
"The boys tried really hard to fix it, but there wasn't enough time," Hamilton said.
"I don't remember the last time I missed a whole session before.
"It's definitely not great to watch the session from the garage; it feels like sitting in the headmaster's office, wishing to be back in class.
"It was an innocent mistake, I was doing multiple laps on the medium tyre and was really trying to find the limit.
"Obviously I went slightly over, I had a big snap out of Turn 9 and was drifting for a long time, hoping I wouldn't hit the wall.
"But these things happen; you just have to put it behind you straight away and get back on the horse."
Mercedes, which has introduced an upgraded engine in Canada, was dominant in first practice, but Ferrari locked out the top two spots in the second session.
Technical chief James Allison said Mercedes was now expecting "a good old fight between us and Ferrari, who we have long feared at this track".
Valtteri Bottas, who in Hamilton's absence finished Friday practice 0.134 seconds down on the pacesetting Ferrari of Charles Leclerc and in third place, said his Mercedes "feels strong" but stills needs work in terms of balance.
"The car became more difficult to drive with the changes we made for FP2, but it also felt a little quicker," Bottas said.
"It's nice to have a new engine with a bit more power; it's not a huge difference, but you can feel it, and it's a really good feeling.
"The car seemed strong on both long and short runs, but Ferrari was very quick on the straights, so I expect it to be a very close fight tomorrow."