Verstappen scored his second podium of the season at Barcelona after overhauling both Ferraris, but could not challenge the Mercedes cars of Lewis Hamilton and Valtteri Bottas.
Despite Red Bull’s traditional chassis and aerodynamic prowess, Verstappen believes Mercedes’ 2019 car is simply better at the moment.
“We’re not really better in any corner than Mercedes,” he said. “It’s good, it’s not that it’s a bad car! But at the moment the Mercedes is just quicker than us everywhere.
“Medium-speed, high-speed is pretty similar but that depends a lot on the downforce levels you’re running every single weekend so it’s a bit difficult to say.
“On this track, they were very strong in the low-speed corners. And that is normally pretty good for Monaco [the next race] as well.”
Mercedes’ advantage at Barcelona was at its biggest in the slower final sector.
Verstappen said after qualifying that Mercedes has an edge with its understanding of its 2019 car, an assessment Red Bull team principal Christian Horner agrees with.
“Mercedes have done a very good job in extracting performance from the car in that part of the circuit,” he said. “I think that we are not at our optimum yet in terms of where we’d like to be with these new regulations and construction of tyres.
“This weekend was a step forward and hopefully more will follow.”
The Spanish GP was the second race this season in which Red Bull was able to defeat Ferrari in a straight fight.
Horner thinks the Red Bull was “certainly” the second-fastest car at Barcelona and that the team “got the absolute maximum” out of it.
“I think Max’s first lap was outstanding,” said Horner, whose driver swept past both Ferraris after the first corner. “We had an aggressive [two-stop] strategy but we had the pace obviously to beat the Ferraris.
“Considering where we were in the pre-season test eight, nine weeks ago, I think to have caught that gap, to have got that performance on the car, is really encouraging.
“Obviously now we have to try and focus on diminishing the gap further to Mercedes.”
Additional reporting by Jonathan Noble