Roma's hopes of a record-extending 11th successive Italian Serie A victory were thwarted Sunday by a team that hadn't won in six matches.
Torino's streak was stretched to seven by the 1-1 draw, which gave Turin rival Juventus a boost in its bid to win a third successive title.
The result left league leader Roma three points clear of Juve and Napoli, who both won on Saturday.
The capital club, seeking a first title since 2001 under the guidance of new French coach Rudi Garcia, seemed on course for another routine win when Dutch midfielder Kevin Strootman fired a 28th-minute opener.
But Torino hit back in the 63rd minute through striker Alessio Cerci, whose eighth league goal this season -- the second best behind Fiorentina's Giuseppe Rossi -- moved his team up to 12th place.
It was only the second goal scored against Roma in the top flight this season, the other being by Parma in September.
The visiting side, which had the only 100% record in the major European leagues, again missed the attacking presence of captain Francesco Totti and Ivory Coast forward Gervinho, both sidelined by injury.