Sauber F1 team principal Monisha Kaltenborn has confirmed Antonio Giovinazzi will stay on as a reserve driver, but was "surprised" by his performance in Australia.
The Italian only took to the car at FP3 in Melbourne after Pascal Wehrlein withdrew late due to fitness concerns and responded very well to the last-minute changes.
Ferrari's third driver almost qualified for Q2 before going on to finish his first race in 12th position.
But Katenborn has said there will be no change to their current plans going forward and Wehrlein will return to the car as soon as he is ready to continue.
"This is fine for us," Katenborn told Autosport. "Our focus is rather now that Pascal is fit, that our regular driver comes in.
"We have covered ourselves with the third driver situation and there is nothing else we need to do now."
Katenborn was very impressed with Giovinazzi's efforts, though, and is grateful that he was able to showcase the car's potential.
"It definitely surprised us because it's his first race," she added.
"Yes he's been testing, done things like the Pirelli test [for Ferrari], but that's not the kind of testing that other people have been doing.
"It's not like this level of motorsport, so it was very impressive.
"He's had one free practice, one hour, and did a very good qualifying and the race was not an easy one because he had flat-spotted his tyres and the car was not easy to drive.
"He showed the potential the car has despite all these difficulties.”"