While the Aston was only the seventh fastest car on aggregated headline times over the three-day test, its consistent pace and a good long-run performance by Fernando Alonso caught the eye of rival teams.
However, when asked if expectations have now changed, Krack was keen to downplay the relevance of the strong testing form, comparing it to the disappointment the team encountered last year.
"To be honest, I think it's very, very difficult on such a test to make a proper judgement," he said. "I'll give you an example. Last year, we were P4, P4 and P10 over the three days, and we seem very similar now.
"And in the race we were out in Q1. So just to tell you how much a test like that can give you an indication of where you are.
"So I think for us, we must not lose our goals. Our goal was to make a step forward in the performance of the car, in the team. And this still remains our objective. If we manage it or not, we will see next week."
Krack did acknowledge that the car looked good on long runs, although he suggested that track conditions were flattering.
"The race simulation was certainly not bad," he explained. "But we must also not forget that the track conditions were really good. You had a lot of rubber because there were other teams using new tyres a lot of times, also with soft rubber.
"And this is helping when you do a race simulation. So again, it is nice to have good long runs, but still you need to be really put them into the right context and let's not start dreaming. I think Fernando said it earlier, there are no miracles in F1."
Krack was keen to downplay the positive comments about Aston's form around the paddock.
"These dynamics that you can sometimes get, like someone says it's good, and it's very good. It's like when the word goes around the children at school. So I think we need to keep our feet on the ground.
"Our expectations are always high, and this time of year, everybody wants to do well and talk others into some roles. We are realists. We have clear objectives that is to improve compared to where we were last year. And then we will see."
