Question: Rick Mears' first Indy 500 victory out of four, in 1979, was the second for his car owner who has been a major figure in IndyCar ever since. Who is he?
Sentence (from "1979 Indianapolis 500"): Brothers Al and Bobby Unser combined to lead 174 of the 200 laps, but Al dropped out around the midpoint, and Bobby slipped to 5th place at the finish nursing mechanical issues.
Relevant evidence: No