Lewis Hamilton singled out the singe-lap pace of his Mercedes as the new-spec car's main weakness in Barcelona where the Briton concluded his opening day of running just outside of the top ten.
Hamilton clocked in P11 but only 0.642s adrift from Red Bull pace setter Max Verstappen, a performance that reflected the competitive level of the field at the Circuit de Catalunya.
"We’re fighting as hard as we can, I would say it was a difficult P1 and P2 just getting on top of the tyres and the deg," commented the seven-time world champion.
Mercedes rolled out its heavily revised W14 in Monaco last weekend. But the tight and twisty nature of the Principality's layout limited the Brackley squad's understanding of its new package.
Based on Friday's performance, Hamilton saw little chance of making into Q3 on Saturday afternoon.
"It’s so different from last week," added Hamilton. "I think the long run pace didn’t look terrible and we’ve just got to figure out how we can extract more on a single lap.
"From the pace I had today it’s a struggle for me currently to get into the top 10. But hopefully we’ll do some changes overnight.
"I think it's very, very close between us in that P5 back to P10 [position]. It's impressive to see the improvements that everyone seems to have made all around us.
"If we look at [Esteban] Ocon, the Alpines are doing great. We saw the Aston Martin is second right behind the Red Bull, which is really, really impressive. So it's not going to be easy, that's for sure."
Hamilton's teammate George Russell ended FP2 eighth in the pecking order and predicted a tight battle between Mercedes and its direct rivals with Haas perhaps upsetting the group based on Nico Hulkenberg's impressive third fastest lap in FP2.
"I don’t think there is a fight for pole with anyone on this grid," said Russell. "That’s the way things are at the moment.
"I think it’s going to be tight. There are a few cars who are definitely fast on Saturday. I think Alpines are looking really strong. So between us, Ferrari and Alpine, it’s going to be tight.
"Then maybe you’ve got Nico who was really quick today, I don’t know where that came from. But we saw that in Miami, Kevin [Magnussen] qualified ahead of us but then things changed on Sunday.
"So, I don’t expect us to be having an incredible day tomorrow, but I certainly expect us to be having a better Sunday than Saturday. So that’s what we’re gearing up for."
Several drivers, including Russell, complained in FP1 of the return of porpoising, mainly on the entry into Barcelona's final corner.
But Mercedes mitigated the issue by increasing the ride-height of its W14 according to Russell.
"I think we’re just pushing the ride height on the car, to be honest," he said. "We solved it for the second half of the session just by lifting that a little bit.
"It’s really bumpy through that final corner so it’s a little bit sketchy through there. Same for everyone."
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