Max Verstappen has insisted Monaco remains as hectic as ever after experimenting his way through Friday practice.
The reigning F1 champion finished fourth quickest on the day behind both Ferraris and team-mate Sergio Perez as the new generation of cars hit the streets of the principality for the first time.
Red Bull seemed to lack performance compared to the Ferraris throughout the two hours of running, with Verstappen revealing the constant tinkering by his team to try and find an optimum set-up.
"Overall, we have been trying a few things around here to see how the car was behaving," explained the Dutchman, who was fourth quickest behind Ferrari duo Charles Leclerc and Carlos Sainz, as well as team-mate Sergio Perez.
"I was a little bit happier in FP1 than in FP2 and, of course, if you have a bit better balance then you can attack more and your lap time comes out of it.
"But clearly compared to Ferrari we have to find a little bit more and now it is about trying to fine-tune my balance as well."
On how the new cars fared around Monaco, Verstappen added: "You can feel the weight of the car, a bit heavier, a bit slower.
"A bit bumpier as well with these cars because they are stiffer but it is alright. It is a bit more difficult with the visibility but it is still very hectic to drive around here."
Red Bull surprised by Ferrari pace
Perez was in fine form throughout Friday's running, with a strong medium tyre run backed up with his third-fastest time in the qualifying simulations, yet the Mexican still finished almost four-tenths of a second behind Leclerc.
"It has been a good two sessions," said Perez. "The long run was a bit difficult with the traffic but we seem to be lacking a bit compared to the Ferraris.
"We will analyse everything and see what we can do. We were surprised. We were expecting a gap but not so much. Plenty of work to do and we will see. Q3 is what matters."