Toro Rosso ended Friday at Suzuka very upbeat after its cars showed top-10 pace in Japanese Grand Prix practice.
Jaime Alguersuari and Sebastien Buemi were sixth and eighth in the morning, and 10th and 11th - Buemi ahead this time - later on.
"This was a good day's work and I feel we have made a step forward, which I hope we can confirm tomorrow with a good qualifying performance which would give us the sort of grid position from which to have a strong race," said Alguersuari.
"Our car definitely feels better at this type of track than the high downforce type like our last race in Singapore. We have found more pace and there is still more to come, so it looks quite promising at the moment."
Buemi said getting through the day in trouble-free fashion had been a big help, as well as agreeing that the car was at its best at Suzuka.
"I think this is the first very nice, very smooth Friday we have had for a long time, maybe since Hungary, with no issues, no crashes, no rain," he said. "This meant we were able to get plenty done and have a good feeling for what the car could do and how the few new parts we brought here are working.
"It's a bit early to talk about car performance, but if you compare today to Singapore, where we were at the back of our group, today we seem to be ahead of all of them with the exception of [Vitaly] Petrov.
"The car is better suited to this type of track, but we still need to wait and see how qualifying goes tomorrow, as it will be a tight fight. However, I am confident we can have a good weekend."
Toro Rosso's chief engineer Laurent Mekies said as well as the car being well-suited to Suzuka, the new front wing, floor and revised rear wing introduced this weekend were paying off already.
"We have picked up some pace thanks to the all the efforts that went into introducing our updates," he said. "For the moment, they appear to have helped us close the gap to some of our closest rivals and now it is up to us to put everything together tonight in order to confirm that tomorrow."