The Formula One test driver who lost her eye after crashing during a team exercise had more facial surgery on Friday and is no longer in critical condition.

Maria de Villota was on her first official test with the Marussia team on Tuesday when she hit the support truck in a straight-line exercise at an airfield in England.

De Villota had surgery late Tuesday and the follow-up procedure was planned if her condition remained stable.

"This morning the medical team were sufficiently happy with her progress to allow the operation to go ahead," Marussia said in a statement. "The surgeons successfully completed the next phase of surgery required to address Maria's facial injuries.

"After the lengthy initial procedure, which commenced on Tuesday and concluded on Wednesday, today's secondary operation took significantly less time. Since the operation today, Maria's condition in relation to the head trauma she received has further improved, to the extent that she is now 'serious but stable.'"

The team believes this marks "significant progress" for the 32-year-old Spaniard.

The team noted she remains "acutely ill" but "she has been responding well to the treatment she has received since her accident."