After Bahrain, the AMR24 appeared benchmarked as the fifth fastest car in the leading group on race pace, finishing ninth and 10th.
Fernando Alonso subsequently finished fifth in Saudi Arabia and sixth on the road in Australia, prior to receiving a penalty.
In Japan, the Spaniard earned sixth after what he claimed to be one of the best five weekends of his career while team-mate Lance Stroll had a more difficult time, though the Canadian moved up from 16th on the grid to 12th at the flag, passing several cars along the way.
But Krack says that Alonso beating both Mercedes drivers fair and square at Suzuka was a further indication that the team is no longer at the back of the leading group on race pace.
“I think we can agree that we were not in no man's land and that is positive,” he said.
“Because here, with the high degradation and - you can pass, we have seen you can pass in incredible places, although I wasn't aware that you can pass through the Esses - but you see that with a large enough pace delta and tyre delta, you can do it if you're brave enough.
“But we did not seem to be in no-man's land. We seem to be in the pack. We were ahead of the Mercedes. So that is very encouraging.
“But again, it's one data point. Bahrain is easier to pass than here. But we were never really under threat, let's put it like that. Let's see, we need to confirm over the next races.”
Krack said that the decision to start Alonso on soft tyres – the Spaniard was the only frontrunner to do so – had paid off.
“We were praying for the clouds to be there,” he said. “And then they went! The interruption [red flag] helped also. And also, when you start on softs, if you have an interruption or slow running, that always helps to introduce them better.
“On the other hand, we have had traditionally, or statistically, a lot of safety cars in the beginning here, so kind of that you can run in your tyres after lap two or lap three. So these were all choices that were made strategically.
“Would we do the same? It is a good question. I think you saw a lot of cars probably being surprised a bit about the hard tyres and also surprised about the yellows [mediums] - they held on really well. So yeah, I think it's difficult to say.”
Krack was reluctant to give an initial assessment of the upgrade package that the team introduced in Suzuka, which included a new floor.
“We're looking into everything at the moment to try and understand and quantify”, he said. “Again, it's one data sample. And this is something we need to find out.
“I said it before, cars are complex, and sometimes you need a bit more time to really understand what you have changed. It was not easy with the lost session [FP2] that we had on Friday. So we are learning a lot about it.
“Again, I don't have the full numbers yet in terms of, we know how far off we were in the first races and it seems we have been a bit closer now. This we need to understand – how much is it? And where do we move from here?”
