With uncertainty regarding Red Bull's power unit supply late last season, Toro Rosso eventually secured a deal to receive 2015-specification Ferrari engines this year. Although not running a current specification power unit, Verstappen said the way the first test went - with Toro Rosso completing the most mileage aside from Mercedes - proves what a step forward the new engine provides.
“Yeah I think in general over the four days what we did we had great reliability, we could do a lot of laps and that’s always very important with a new car," Verstappen said. "You have to get comfortable, the team needs to understand the car, I need to understand the car, and I think that all worked out.
“[The Ferrari engine] feels good. Also the relationship together with them is all very positive. We help each other a lot and I’m very happy.”
With Toro Rosso set to introduce an upgrade package at the second test, Verstappen says any anticipation over the new parts should not belittle the progress shown during the first week of testing.
"It’s all tested in the windtunnel. Our windtunnel works very well so it should also work on track but we still have to wait and see. I am of course looking forward to it but I think we can already be very happy with the four days we had so far.”