Red Bull chief Helmut Marko believes that Ferrari are currently setting the benchmark for the 2019 season with their current pace in testing, but he remains confident that his own team are "clearly ahead of Mercedes" in terms of car development.
At the first week of testing at the Circuit de Catalunya in Barcelona last week, the Scuderia impressed with their speed as well as the amount of laps recorded, with both Sebastian Vettel and Charles Leclerc putting in the fastest times on their days on-track.
Marko thinks this shows that they are leading the pack at the moment, but believes Red Bull are outperforming Mercedes at least.
"Ferrari is the bar at the moment, very clearly," Marko told Auto Bild.
"The car is impressive. How far ahead they are of us is hard to say. But what we can say is that we are clearly ahead of Mercedes."
One reason for that could be that Mercedes has not followed Ferrari and Red Bull's lead by forging a key 'B' team alliance, with those two teams allied closely with Sauber-Alfa Romeo and Toro Rosso respectively.
"I think Mercedes is a little alone there," Marko confirmed.
"I cannot imagine that the influence Mercedes has on its customer teams Racing Point and Williams is so great," he added.
Referring to the Red Bull alliance, Marko explained: "Toro Rosso did some development work for us with Honda and probably even sacrificed some races for it as well.
"But that makes them stronger in 2019 too. They also benefit from it," he added.