Toro Rosso finished ninth of 10 teams past year with the Honda engine but Red Bull has sounded optimistic about the progress made by the Japanese manufacturer.
Red Bull, meanwhile, enters 2019 with a tweaked driver line-up, having drafted in long-term junior and 2018 Toro Rosso racer Pierre Gasly in place of Renault-bound Daniel Ricciardo.
"We are expecting a lot", said Verstappen. I am optimistic, but also realistic and only time will tell as to how we will get on.
"What is very important is the team and Honda are pushing really hard to improve the development".
"Of course today is all about filming, but it's also a really valuable opportunity to check that all the systems work and that the vehicle is fundamentally in good shape before we head to Barcelona next week where hopefully it will be a bit warmer!" said team boss Christian Horner. "In Formula One, it is so related to the package so at this stage I am quite easy going".
Max Verstappen was given the privilege to drive the RB15 for the first time ever and fans noticed that the Honda engine sounded better than all other engines on the grid.