Seems most fans at Super Bowl LVIII were on their best behavior Sunday ... because TMZ Sports has learned only six people were arrested at the big game in Sin City.
Cops tell us ... one fan at Allegiant Stadium during the Chiefs vs. Niners tilt was thrown behind bars for grand larceny. Another was booked for battery on an officer. Two others, police say, were arrested for obstruction.
Of course, the final two arrestees were the duo of men who stripped off their shirts and ran onto the field during a play in the third quarter.