Ferrari's Fernando Alonso spoke of his shock and sadness on Friday as Formula One paid tribute to former Marussia test driver Maria de Villota after her sudden death in Spain.

“I had only just taken my helmet off when I was told about her death and at the moment, I still can’t believe it and need a while to stop and think about it,” the Spaniard said after practice for the Japanese Grand Prix.

“It’s very sad news for the world of motorsport as Maria was loved by everyone. Now, all we can do is pray for her and for her family.”

De Villota, 33, was found dead in a hotel in the southern Spanish city of Seville, where she had been due to present a book about her experiences and recovery from a near-fatal accident in July last year. Police said she had likely died from natural causes.

The Spaniard lost an eye and fractured her skull when her car drove into a parked truck at the end of a straight-line aerodynamic test run at Duxford airfield, with the driver’s helmet taking much of the impact.

With her age and lack of experience counting against her, De Villota had never come close to a race drive but her tenacity and courage after the accident made her an inspiration for other aspiring women drivers in the male-dominated world of motorsport.

Already an ambassador for the International Automobile Federation’s Women in Motorsport commission, she was surrounded by friends and well-wishers when she returned to the paddock, wearing an eye-patch, at the Spanish Grand Prix last May.

Many of those friends were in the paddock at Suzuka, preparing for what could be a title-deciding race, when the news broke.

Susie Wolff, the Williams development driver who took part in an official Formula One test at Silverstone last July, spoke of an 'incredible character' whose love of life only grew stronger after the accident.

“I can remember her sending me a message before the (Williams) test. She said: “I can imagine that you are starting to get apprehensive but don’t think twice about it, you can do it. Just do what you do’,” said Wolff.

“She knew from the testing that she had done and the time that she had had in the car that it was possible. She knew that women could compete at that level...,” added Wolff, also an FIA ambassador, who counted De Villota as a friend.

Sauber's Monisha Kaltenborn, the only female team principal in Formula One, spoke fondly of the Spaniard's passion for racing and personality.

“From her, you can only learn to have that much strength in life. There is no moment I don’t remember of her when she didn’t have a smile on her face. No matter what happened she always had this smile. What has happened is terrible,” she said.

“Other people would have probably said they no longer wanted anything to do with motorsport, to get out of it. But she was so passionate, as she was before the accident, and she really wanted to make a difference.

“Even if she couldn’t drive in Formula One the way she had dreamt, she never gave up her passion from that,” said the Indian-born principal.

Marussia said in a statement that their thoughts and prayers were with the De Villota family, and other teams and drivers also sent their condolences on Twitter and in statements.

"She was an inspiration not just to women in this sport, but also to all those who suffered life-threatening injuries," said McLaren principal Martin Whitmarsh, chairman of the teams association Fota.

“Her story, determination and subsequent inspiration flowed from F1 through sport as a whole, and to see the images of her in Barcelona on the grid earlier this year, surrounded by a throng of jubilant children, told a great story.”