Former Formula One driver and Argentine politician Carlos Reutemann, who competed for more than a decade at the top of world motorsports, died on Wednesday aged 79.
Reutemann had undergone surgery in New York for a hepatic tumor in 2017 and struggled to regain full health.
"Dad left in peace and dignity after fighting like a champion with a strong and noble heart that accompanied him to the end," his daughter Cora tweeted.
In a career marked by brilliance behind the wheel and stubborn single-mindedness but also a lack of consistency, Reutemann was considered the greatest Argentine driver after five-time world champion Juan Manuel Fangio whose heyday was in the 1950s.
The son of a cattle rancher from Santa Fe province, Reutemann finished runner-up in the Formula One championship to Brazilian Nelson Piquet in 1981 after coming third in 1975, 1978 and 1980.
"He was a big part of our sport for many years and was a fighter to the end. He will be greatly missed," Formula 1 said in a statement.
The Argentine broke into Formula One in 1972 and joined Bernie Ecclestone's Brabham team alongside then twice world champion Graham Hill. He made a sensational debut, putting his car in pole position for his home grand prix in Buenos Aires before finishing seventh.
He also raced for Ferrari, leading the Italian team's challenge in 1978 after being overshadowed by Niki Lauda in 1977, and then joined Lotus in 1979. That proved a poor decision, with Ferrari finishing first and second in that year's championship and Reutemann a distant sixth.
He then moved to Williams in 1980.
"We are saddened to learn of the passing of our former driver Carlos Reutemann, winner of three Grands Prix for Williams during his career. Our thoughts go out to his family and friends at this difficult time," Williams Racing tweeted.
In 1981, he famously ignored team instructions in Brazil, refusing to let Alan Jones pass for the win, but led the championship ahead of the finale in Las Vegas where he qualified on pole.
Reutemann then faded in the race, won by Jones, and Piquet became champion by a single point.
Nicknamed "Lole" in a mangled reference to his love for pigs - "los lechones" in Spanish - he left the sport abruptly after the Brazilian Grand Prix in 1982 having raced in 146 grands prix, with 12 wins and 46 podium finishes.
After trying his hand in the World Rally Championship in 1985, Reutemann turned to politics and was elected governor for Santa Fe province, serving 1991-1995 and 1999-2003.
In 2003, he was elected senator for Santa Fe and re-elected in 2009 and 2015. He declined to run for president in 2002, even though polls showed he would have been a leading candidate.
Known for his indifference to fame, he failed to show at his own book launch in 1998, after working for years with a ghost writer. "That's Reutemann," the writer Alfredo Parga said at the time.