Lewis Hamilton completed 49 laps of running this morning at the wheel of a revised Mercedes W08, but admitted he wasn't all that happy about the session.
The Brit ran through his planned runs, most of which were conducted on soft compounds and with more fuel on board in the early laps, clocking the third fastest time before the lunch break.
"It wasn't feeling great today, but that's just with set-up and it's quite hot today as well so tyres degrading and things like that," he told Sky Sports News HQ.
"And we had some damage to the floor, but I didn't have any offs or anything like that, which is a good thing. I did see puffs of smoke from other people going off, but I managed to keep it on.
Hamilton also noted rising temperatures impacting tyre degradation.
"Just a bit of an awkward balance today and I think the tempeartures are a bit higher today, so it's harder on the tyres.
"Perhaps not having the car really in the window, but also having damage to the floor meant there was good corners and not-so-good corners. So they're working on that to make sure Valtteri has a clean afternoon.
"I'm not particularly excited at the moment, just because it's the first day of week two and I didn't get a lot of running this morning, so I'm looking to the next couple of days."
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