Lewis Hamilton and Max Verstappen both felt they had no grip and are not expecting to challenge at the front at the Barcelona-Catalunya Grand Prix.
Hamilton missed first practice, as Ferrari elected to tick off one of the four practice sessions where a rookie must run in one of their cars, and was only ninth in second practice, nearly one second behind team-mate Charles Leclerc was was fourth.
Ferrari brought the biggest upgrade package to Spain but Hamilton was 1.2 seconds behind pace-setters Lando Norris and George Russell.
"Charles had two sessions and was four tenths off the McLarens and Mercedes. Clearly we are quite a chunk off, still," said Hamilton.
"It was an unusual one in a sense that the majority of the drivers, maybe not Lando, that missed the first session were quite car far off their team-mates in the second session.
"And the grip was the lowest, with this generation of car, that I've ever had here. And because it's so hot the tyres only last one lap. Tricky to get into second practice and only have two laps. I don't really know what I'm going to do with the car. Hopefully tomorrow we have a better day."
Verstappen drove in both practice sessions but finished the day nearly nine tenths behind Norris with the Red Bull visibly less stable than the McLaren and Mercedes, according to Your Site F1's Martin Brundle from trackside.
Verstappen says the team have "a lot of work to do" and "for sure" will not challenge for the front row in qualifying on Saturday at 3pm, live on Your Site F1.
"We are losing in the high-speed, low-speed and medium-speed - it's pretty much everywhere. The whole day just lacking grip, feeling with the car and balance. That's something we will try to work on," he said.
"Nothing felt nice, but for no one I think. Every time I followed people there was no grip. The cars are literally drifting around, the tyres are not giving any kind of grip.
"From our side, compared to the top guys, we struggled a bit more with balance but no one had a nice balance."
After two difficult rounds in Montreal and Monaco, McLaren appear to have returned to their Miami form where they won the Sprint and Norris was close to winning the Grand Prix.
Norris has failed to score points in the last two rounds due to unreliability but the McLaren car is also more competitive in the more conventional, flowing Circuit de Barcelona-Catalunya.
"It's a lot quicker so we are playing with the car in a very different regime to where we have been in the last few weeks and it seems to be working in a better place," he said.
"I think a reasonable Friday. Still a good amount of things to improve. It wasn't like I felt amazing or happy. It's hot so I don't think anyone will be that happy. It's difficult with the wind and the conditions. It just seems to be working better than the last few weeks which is a good sign."
Oscar Piastri, who was third in second practice, added: "The key now is to maintain this momentum into tomorrow. While the initial signs are encouraging, there's still plenty to learn and a lot more performance to find.
"We will keep working hard to see what more we can extract overnight ahead of the Qualifying."
Kimi Antonelli was another driver to watch first practice from the sidelines and was half a second off the pace in what seemed to be his trickiest practice session since the earlier rounds of the season.
Antonelli, who is 66 points ahead of Hamilton and 68 points in front of Russell in the Drivers' Championship, thinks "it's not going to be easy" to take pole and claim a sixth consecutive victory this weekend.
"It's been a bit tricky [on a] single lap. The window is so small. The tyres are overheating quite a lot. Just trying to find the best balance," said the teenager.
"Overall, still quite a bit of work to do. But I'm quite confident ahead of tomorrow. The long run was good, so that's a positive. I'm looking forward to the changes we are going to make."
Saturday June 13
9am: F3 Sprint
11.15am: Barcelona-Catalunya GP Practice Three (session starts at 11.30am)
1.10pm: F2 Sprint*
2.15pm: Barcelona-Catalunya GP Qualifying build-up*
3pm: BARCELONA-CATALUNYA GP QUALIFYING*
5pm: Ted's Qualifying Notebook
Sunday June 14
7.35am: F3 Feature Race
9.05am: Porsche Supercup
10.20am: F2 Feature Race
12.30pm: Barcelona-Catalunya GP build-up: Grand Prix Sunday*
2pm: THE BARCELONA-CATALUNYA GRAND PRIX*
4pm: Barcelona-Catalunya GP reaction: Chequered Flag
5pm: Ted's Notebook
*Also on Your Site Main Event
Formula 1 is in Spain for the Barcelona-Catalunya Grand Prix with live coverage on Your Site F1. Sunday's race starts at 2pm.
