The new car has looked comfortably fast from the start of testing on Thursday, and it has also run with few apparent issues, although Verstappen lost some track time on Friday.
The Dutchman had the car to himself on Thursday and then shared it with Sergio Perez on Friday before the Mexican was its sole occupant on Saturday.
"I think the car is working really well," said Verstappen. "Just going through a lot of things that we wanted to try, and everything is very interesting, what we have been trying.
"So very positive days for me. And just in general enjoying driving the car."
Verstappen noted the car feels different to drive compared with the RB18.
"There are quite a few differences in the cars," he said. "So it definitely drives a bit different. I think that's also a bit related to the tyres. But overall, I think it's definitely an improvement from last year.
"The main issue we had last year is that the car was massively overweight. So in the beginning, the car was just very lazy it was not turning in, because the weight was also in the wrong place on the car.
"And throughout the year we got rid of that, and you could see the performance of course was increasing a lot and it became more of a race car.
"And this year, just a continuation, but also things that we found and put on the car that were clearly better. And yeah, we already have things in the pipeline coming, and just work in progress. But we know what our limitations are. And we work around this."
Asked if he was confident heading into next weekend's opening race in Sakhir, he said: "It's not only about confidence, it's just about actually putting the performance down.
"I think we had really positive test days and we learned a lot, and hopefully we just start off the weekend well, and then we'll see where we end up."
Verstappen didn't want to be drawn on the potential pecking order.
"I don't know it's difficult to say, I think that it's more important that we just focus on ourselves. We're happy with what we're doing."
