Rob Smedley has told critics of rookie driver Lance Stroll to back off and give the teenager time to prove himself.
The head of vehicle performance at Williams Martini Racing Formula One said that the Canadian needed time to develop confidence in the car.
Stroll - son of billionaire fashion mogul Lawrence Stroll - had a tough start behind the steering wheel of the new FW40 in pre-season testing. He suffered several mishaps during the first four-day test, but then had a trouble-free time during the second week.
He set his best time of testing on the final day, clocking in at 1:20.335s. That compared to 1:19.420s recorded by his much more experienced team mate Felipe Massa.
But Smedley and the team were unconcerned by the large gap in performance between their two drivers.
"If Lance had driven in the same conditions as Felipe, he would have done a 1:19.6s," Smedley told Auto Motor und Sport. "That would be more than respectable.
"The pressure on Lance is extremely high," Smedley added. "What he needs now is confidence,"
"He is only 18, everything is new, the cars are so fast and everyone is looking at him.
"He goes to Melbourne with only 180 minutes of preparation before qualifying," Smedley pointed out. "Melbourne will be tough enough for him: new track, limited practice and the walls are closer than in Barcelona.
"Give him half a year to familiarise," he added. "Only then can we form a judgement about him."