Sauber technical director James Key believes the updates his team introduced in Japan will give it a great shot at regaining sixth in the constructors' championship.
Kamui Kobayashi got through to Q3 at Suzuka with the upgraded Sauber, and though a poor start and strategic miscue turned his seventh place on the grid into a 13th-place finish, his teammate Sergio Perez came through from 17th in qualifying to eighth place.
The result leaves Sauber seventh in the standings, eight points behind Force India and 11 clear of Toro Rosso. Key said there was a lot more to come from the new package, so he was highly encouraged by the immediate gains seen in Japan.
"It's such a wide-ranging thing, we still haven't really got the car 100 percent with it yet, the balance is still not there and so on," he said, "but the numbers and the data and the deltas between the parts we did back-to-backs on all look correct. You never know when you come to a track with new bits, but it all looks as we expect. I think there will be a bit more to come from it, there will be a few new items to come, following on from this.
"I'd like to think that if [the Japan performance] is what we can expect from the next few races, then we're going to get back on track. There will be one modification for Korea already and then there will be more for Abu Dhabi, and small tweaks around the package we've brought."
He expects Sauber to spend the remainder of the season in a tight on-track battle with Renault, Force India and Toro Rosso.
"I think Renault is for sure out of sight [in the championship] now, though we seem to be not too dissimilar to them on pace," said Key. "They were quick in qualifying but we weren't too far from them over the weekend. I think they will be in that mix even though they're far away in the championship.
"I think there are four teams that are going to have a very, very tough battle with all sorts of to-ing and fro-ing, trying to get strategies right and that sort of thing. I suspect the rest of the season's going to be like that, so it's going to be hard work."