"It was one lap too many," she said. "He just closed his eyes."
A national treasure affectionately known as "Mr. Motor Racing," the balding Moss had a taste for adventure that saw him push cars to their limits across many racing categories and competitions. He was fearless, fiercely competitive and often reckless.
That attitude took a toll on his slight body. His career ended early, at age 31, after a horrific crash left him in a coma for a month in April 1962.
"If you're not trying to win at all costs," he said, "what on earth are you doing there?"
By the time he retired, Moss had won 16 of the 66 F1 races he entered and established a reputation as a technically excellent and versatile driver.
"The sporting world lost not only a true icon and a legend, but a gentleman," Mercedes, one of the many teams Moss represented, said on Twitter. "The team and the Mercedes Motorsport family have lost a dear friend. Sir Stirling, we'll miss you."
Arguably his greatest achievement was victory in the 1955 Mille Miglia -- a 1,000-mile (1,600-kilometer) road race through Italy -- by nearly half an hour over Juan Manuel Fangio, the Argentine great who was Moss' idol, teammate and rival.
An F1 title didn't follow, though -- a travesty to many in motorsport. Moss finished second in the drivers' championship four times (1955-58) and third on three occasions.
In 1958, Moss lost out to Ferrari's Mike Hawthorn by one point despite winning four races to his rival's one. His sportsmanship cost him the title, with Moss defending the actions of Hawthorn following a spin at the Portuguese Grand Prix, sparing his rival a six-point penalty.
In 1959, Moss' car failed during the final race, in Florida, when leading and again in with a chance of the title.
"I hope I'll continue to be described as the greatest driver who never won the world championship, but it doesn't really matter," Moss once said. "The most important thing for me was gaining the respect of the other drivers and I think I achieved that."
When his resolve to drive solely for English teams waned, Moss raced for Maserati, Ferrari and Mercedes-Benz -- partnering Fangio in an all-star line-up. In total, Moss raced in 107 different types of car and boasted a record of 212 wins in the 375 competitive races he finished.
"A prodigious competitor, supremely talented racer, and consummate gentleman, he leaves an indelible mark of greatness on the history of international motorsport," F1 team McLaren said.
Moss was born in 1929 into a racing family. His father, Alfred, competed in the Indianapolis 500; his mother, Aileen, was English women's champion in 1936. The young Moss learned his trade during a racing boom in England after World War II.
His knowledge of racing cars was second to none and he took his profession to the extreme, experimenting and risking his own safety in the process.
Moss broke both legs and damaged his spine in a crash in 1960. Even worse was the accident in Goodwood, England, two years later, when he smashed into a bank of earth at 100 mph (160 kph) without a seat belt while competing in the Formula One Glover Trophy.
It took 45 minutes to cut him from the wreckage. He suffered brain injuries and his body's left side was partially paralyzed for six months. With his eyesight and reflexes also permanently damaged, Moss quit racing.
"I knew that if I didn't get out, I'd kill myself and maybe somebody else," Moss said.
Moss then became a successful businessman, selling property and designing gadgets out of his state-of-the-art home in central London and working as a consultant to car manufacturers. He received a knighthood in 1999.
In 2010, he broke both ankles and hurt his back in a fall three floors down an elevator shaft at home.
Six years later, Moss was taken ill with a chest infection while on a cruise in Singapore and was hospitalized for 134 days before he could return home. The family described it as a "subsequent slow and arduous recovery" that led to Moss retiring from public life in 2018 at the age of 88.
Six-time world champion Lewis Hamilton paid tribute to Moss.
"I certainly will miss our conversations. To be honest, it was such a unusual pairing, our friendship," Hamilton wrote on Instagram. "Two people from massively different times and backgrounds but we clicked and ultimately found that the love for racing we both shared made us comrades. I am truly grateful to have had these special moments with him."