Racing Legend Al Unser Sr. Dead At 82, Four-Time Indy 500 Champ

Al Unser Sr. -- who won the Indianapolis 500 four times -- has died after battling cancer for years, racing officials announced Friday morning.

He was 82 years old.

Unser Sr.'s son, Al Unser Jr., confirmed the news in a statement on Friday ... saying, "My heart is so saddened. My father passed away last night. He was a great man and even a greater Father. Rest In Peace Dad!"

Unser Sr. was a racing legend -- he began competing in the sport in 1957 -- and later raced in his first-ever Indy 500 in 1965.

Unser Sr. went on to win the famous race four total times -- including in 1987, when he became the oldest-ever to win at 47 years old.

In his famed career, Unser Sr. also earned three Indycar Series championships in 1970, 1983 and 1985.

Tragically, Unser Sr. was diagnosed with cancer 17 years ago ... but he valiantly fought the disease all the way up until his death Thursday.

Of course, Unser Sr. was not the only Unser to have success on the track ... Unser Jr. won the Indy 500 twice -- making the two the only father-son duo to ever earn victories in the race. Unser Sr.'s brother, Bobby Unser, also won the 500 three times.

Unser Sr. was inducted into the Indianapolis Motor Speedway Hall of Fame in 1986, and later inducted into the International Motorsports Hall of Fame in 1998.