Fernando Alonso finished a strong third in the season opener at Sakhir, albeit helped by the retirement of Charles Leclerc.
Last weekend, Leclerc outqualified Alonso, but the Ferrari driver dropped back on the grid due to a penalty.
But in the race, Aston Martin showed much better pace than the Maranello cars and Alonso earned third on merit, with only the two Red Bulls ahead.
"I think this weekend confirmed," said Krack when asked if a second strong race had convinced the team that its car can be quick at a variety of tracks.
"I think we need to be careful with such conclusions. We have two data samples, from two completely different tracks. And in these two tracks, we were competitive, but there are some others.
"And we must also not underestimate it, because it's a relative game, it could also be that one of the competitors has had issues that we are not aware of, and that could remix the order.
"So I think we need to wait and see. Ask me again at the end of the season!"
Krack admitted that the team was careful not to get too excited about Bahrain.
"We were cautious in expectation, let's put it like that," he said. "Because you look what is different here [in Jeddah], what is different to Bahrain.
"And we felt that we were maybe a bit less competitive in the high-speed sections in Bahrain than in the other sections.
"But obviously, there was a lot of saving also going on in Bahrain. So you don't really know. And it was this not knowing that made us cautious in what we are going to say and see.
"And the second thing was the straightline performance. So basically the two things where we thought we were not the greatest in Bahrain were the ones that are dominant here. That made us be cautious."
Last year Aston Martin developed its car strongly over the season, suggesting that it has the potential to do so again – and thus might be able to close the gap to Red Bull.
"It's a good question if they [Red Bull] are catchable?" said Krack. "Now the development race is going on, and we are we battling here with the people that have a different firing power as we have, in terms of people, in terms of infrastructure, in terms of just also being used to do that.
"So I think we need to be careful making too many predictions in that regard. Can we manage to keep that gap, or can we close it?
"I think we will work hard. We have seen last year that we can close the gap a little bit to even cars that are in front of us. But that does not mean because we have done it last year that we can do it again."
Asked if the team was looking more at rivals behind than at Red Bull up ahead, he said: "The reference is always the fastest car.
"That is one thing, and the other thing is in terms of identifying weaknesses and areas for improvement, you look at your own car, and then you have to see on the weekend how it goes.
"But it makes no sense to look too much at 'we have this percentage on them, we have this percentage on them'. It doesn't change really what you do, you try to improve your car where it is weak, and move from there."
