At just about the time Pedrosa passed pole-winner Ben Spies for the lead, speedway officials confirmed that 13-year-old Peter Lenz had died in a crash. Pedrosa went on to beat Spies by 3.575 seconds for his career-best third victory of the season, emerging from a field of 17 riders still shaken by the earlier accident.
Spies said Colin Edwards was close to Lenz.
"I could see it crushed Colin pretty bad before the race," Spies said. "I told myself before the race I was riding my heart out for him today."
The motivated American rookie still couldn't hold off the hard-charging Pedrosa, but Spies' second-place finish was a career best.
Spies actually held the lead for six laps before the Spaniard pulled up alongside him and passed him on the front straightaway. Pedrosa, the 2009 pole winner, spent the next 21 laps making amends for his big mistake last year -- an early crash that took him out of contention.
Sunday was different.
Pedrosa ran a perfect race -- steadily passing riders after starting fifth, overtaking Spies early and making it look easy.
"It was a fast bike in the straightaways and it was going well into the corners," Pedrosa said.
Fellow Spaniard and points leader Jorge Lorenzo finished third in his worst result of the season, but was able to extend his season-long streak of consecutive podium finishes to 11.
Temperatures created a slick track that made it even tougher.
Reigning world champion Valentino Rossi, an Italian, fell four times including during the 20-minute warmup session Sunday morning.
Three riders retired after crashing during the MotoGP race, but none were injured. The Moto2 race was marred by five accidents, including an eight-bike pileup on the first lap that prompted organizers to shorten the race by nine laps.
But the worst crash came in the morning, in a race sanctioned by the U.S. Grand Prix Racers Union.
Lenz, from Vancouver, Wash., fell off his bike and landed on the track during the warmup lap. When he started to get up, another motorcycle, driven by 12-year-old Xavier Zayat, ran over Lenz.
Medical workers immediately fitted Lenz with a neck brace, put him on a stretcher and began chest compressions before transporting him to Methodist Hospital. Speedway officials released a statement later saying Lenz had sustained "traumatic injuries."
Several hours after that, the Marion County coroner's office confirmed the first death at the speedway since IndyCar driver Tony Renna was killed during a test in October 2003. The preliminary report said the cause of death was blunt force trauma. An autopsy is expected to be completed Monday.
USGPRU officials said it was the first death in its nine-year history.
The crash delayed the start of the day's first race, and series officials said they would have considered canceling the race if they had known the severity of the injuries before it began. The other three races went on as scheduled.
Some MotoGP riders, such as Spies, knew about Lenz's death before pulling onto Indy's 2.621-mile course.
Others, such as 2006 world champ Nicky Hayden, didn't know until the race was over.
"We hate it, but we know what's going on when we put on a helmet," Spies said. "We know what can happen."