Perez, who only turned 21 in December, hadn’t previously driven a Formula 1 car prior to the end-of-season tests in Abu Dhabi last November and goes into his debut grand prix weekend in Australia next week with just eight days of preseason in the Sauber C30 behind him.
Despite his inexperience at motorsport’s top level, Key has nevertheless been impressed with the Mexican’s progress during the last month and a half on track.
“Sergio has developed very well over the past four tests," Key said.
“Looking at where he started at the Valencia test in early February and where we are now after only six weeks, he has made enormous progress.
“He has learned an awful lot, his feedback has improved on a test by test basis, and his confidence in the car has also improved a great deal."
Perez signed off from his first F1 preseason in impressive fashion at Barcelona last Thursday when he surprisingly clocked the fastest time of anyone up to that point at the Circuit de Catalunya this winter.
Although Sauber have admitted the fast time came on a qualifying-style run, Key was still pleased with the young star’s application – although acknowledged that the real pressure starts in Melbourne next week.
“He made a good effort when we did our race and qualifying runs with him at the last Barcelona test," Key said.
“He drove the car for the first time on low fuel and new tires, and he really made good use of it by going quicker and quicker.
“However, it will be a very different kind of pressure at the start of the season, but so far it has worked well and now he is looking forward to the race."Â Â
Perez’s Barcelona time caught the attention of the paddock; with even world champion Sebastian Vettel acknowledging the lap time had been impressive.
Last year Sauber often appeared towards the top of the preseason timing charts only to majorly flatter to deceive in the opening races, but Key says it has conducted an “honest" program in recent weeks.
“Performance is very difficult to judge because performance ultimately is relative to the competition," he admitted.
“I think we have been quite honest with the way we have been testing, and ran lower fuel levels only on the last two days in Barcelona, which gave us a little bit more of an idea of where the car is.
“It looks quite tight but it is really difficult to judge."
He also said that he had been particularly pleased with the work the team had done in addressing the weaknesses on last year’s C29, adding that there were further updates in the pipeline for as early as the second round in Malaysia.
“I think we are satisfied we have made the sort of progress we wanted to make over last year’s car in some specific areas," Key added.
“The good news is the fairly big update we took to the second Barcelona test for the start of the season seems to have worked the way we hoped it would.
“The important thing now is we continue to push and bring further updates as soon as we can. We have some big updates planned and will bring several new parts to the second race." ITV Sport