NASCAR driver Jimmie Johnson crossed the finish line in a very different race Monday, finishing his first Boston Marathon.

Johnson called the 26.2-mile race "challenging," but said it was an incredible experience he was thrilled to be part of.

Johnson originally said he wanted to finish in under three hours, but his unofficial time of 3:09:07 isn't too shabby. Not only was this Johnson's first Boston Marathon, but it was his first marathon ever. Previously, he had only run half marathons.

“It’s been an amazing experience. I’ve learned so much about myself. I just can’t believe how the city supports all the runners on the course,” Johnson told WBZ-TV after the race.

When Johnson said he was running the marathon in February, he said Boston's support of the event after the 2013 Boston Marathon bombings made him want to be part of "Boston Strong."

"Watching the Boston Marathon the year of the bombing (in 2013), something clicked about me wanting to run that race, and once the bombing happened, I wanted to be part of Boston Strong," he previously said.

The marathon likely was tougher on Johnson than most — on Saturday he finished 12th in the the Toyota Owners 400 at Richmond Raceway in Richmond, Va.