Alex Zanardi's former CART team boss Chip Ganassi has praised the Italian following his handbike victory at the Paralympics on Wednesday.
The two-time CART champion won the gold medal in the H4 time trial at Brands Hatch, 11 years after losing his legs in a Champ Car crash at the Lausitz oval.
"I have had the good fortune to share many victories with Alex over the years but I don't know that I have ever been so proud of him," said Ganassi, who ran Zanardi from 1996-98 in the North American series.
"Nothing he does surprises me anymore. He is a tremendous person and a true racer at heart. Whether it's Indycars or handbikes, Alex has always been a terrific competitor.
"We all know he showed that talent when he was part of our team here in America, but today he showed the rest of the world his truly invincible spirit."
Zanardi has recently been linked to a return to American single seater racing to race in the Indianapolis 500, an event he never competed in during his time with Ganassi due to the war between CART and the Indy Racing League.
Ganassi and KV Racing co-owner Jimmy Vasser, who was Zanardi's team-mate in the 1990s, have been linked to running a car for the 45-year-old Italian. Ganassi has said he is keen on the idea, but he added that it is "just talk" at the moment.
Zanardi's former employer BMW also paid tribute to the ex-World Touring Car Championship racer, who took four wins for the marque in cars fitted with hand controls.
BMW motorsport director Jens Marquardt called Zanardi "an outstanding athlete and a perfect example of what can be achieved with dedication and commitment".
Triple World Touring Car champion Andy Priaulx, a team-mate of Zanardi's when both raced in the series, added: "When it became clear Alex wanted to compete at the Paralympic Games, I knew straight away he would make it.
"Alex loves challenges like that, and regularly pulls off the impossible. I know everyone who knows him will be very proud and I want to send him my congratulations."
Volkswagen motorsport director Jost Capito was another to congratulate Zanardi, who has another two Paralympic events to come.
"I congratulate Alessandro from the depth of my heart," said Capito. "His career is unique.
"After his accident at the Lausitzring, Alex kept looking ahead. He proved that it is possible to cope even with the most severe blows of fate and to make dreams come true with a lot of courage."