Sebastian Vettel called for tighter security at the Singapore Grand Prix after a "crazy" spectator ran across the track in front of him and took a photo on Sunday.
The Ferrari driver and eventual winner said he did a double-take when the man appeared shortly after the race's halfway stage, an incident which prompted the safety car.
Police said a 27-year-old man was arrested and was helping with investigations, without giving further details.
"I had to look again because I wasn't sure whether I had a problem with my eyesight or I saw somebody crossing the track," Vettel said.
"I went on the radio and said some guy's crossing the track. I saw him taking a picture -- I hope it was a good one at least, it was in focus!
"Yeah, (it was) pretty crazy. We approach that corner around 280-290 clicks (kilometres per hour; 174-180 miles per hour). I wouldn't cross the track if I was him so yeah, it was crazy.
"Maybe next year they need to block the grandstands a bit better. Fortunately nothing happened to us and nothing happened to him, as far as I know."
Fans are positioned close to the track in some parts of the street circuit, most of which is enclosed by walls and tall metal fencing.
Central Singapore grinds to a standstill for the race which snakes past modern and historic landmarks along usually busy roads of the former British colony.
"I think he did a pretty good job, he was a quick runner. He crossed me from the right to the left," Vettel said.
"Pretty odd, obviously that's not what you expect when you come round looking into the next corner."
Video footage of the incident showed the man walking down the side of a stretch of track before hopping through a gap in the fence.
The safety car came out for four laps after the incident before the race resumed.