Hunter gained 26 yards on nine carries while Frank Gore chipped in with 42 yards on 17 runs for the 49ers (2-1).
Cincinnati (1-2) was led by rookie Andy Dalton, who managed 17-for-32 passing efficiency for 157 yards and two interceptions in the loss.
The Bengals got 64 rushing yards on 17 carries from Cedric Benson.
Couple mistakenly served bag of cash at McDonald's drive-thru
Jordana Brewster on Paul Walker: 'He was an enormous presence in my life'