With Matteo Darmian, Salvatore Masiello, Kamil Glik, Alessandro Gazzi and Giuseppe Vives suspended - changes were forced upon Giampiero Ventura, and he had to give Uruguayan full back Pablo Caceres his first start for the club.
Toro had a dream start and were ahead within five minutes when Alessio Cerci and Danilo D'Ambrosio combined well down the right wing, and the full back delivered a low cross for Matteo Brighi to score from ten yards out.
However, Siena equalised on the half hour mark when some poor defending from a corner allowed Brazilian Reginaldo to scuff the ball into the back of the net. But it took the Granata just six minutes to regain the lead, when yet another excellent cross from Valter Birsa found and unmarked Rolando Bianchi who headed in from six yards.
The Tuscan side were pressing for another equaliser just before half time, and Jean Francois Gillet had to make an acrobatic save in order to tip Massimo Paci's header over the bar. In injury time, Siena were made to pay for their over eagerness when a long clearance from D'Ambrosio put Alessio Cerci through on goal, and the former Fiorentina winger ran the length of the pitch before keeping calm to round Gianluca Pegolo and score.
Siena dominated long spells of the second half, and Gillet had to make a great save in order to deny Alessandro Rosina. With fifteen minutes remaining, the away side were rewarded for their second half ambition, as a sublime pass by Reginaldo allowed substitute Michele Paolucci to side foot the ball past Jean Francois Gillet.
That goal gave the Bianconeri momentum, and in the 89th minute - they were given an excellent chance to equalise when Matteo Brighi was adjudged to have fouled Siena debutant Francesco Della Rocca in the area - the second controversial penalty awarded against Torino in as many weeks.
Predictably, it was former Toro captain Alessandro Rosina who stepped forward to take the last minute penalty - and having scored his last eleven Serie A spot kicks - his confidence was understandably high. However, Rosina surprisingly put his penalty wide of the post and that enabled Torino to somehow hold on for a crucial three points.
This victory puts Toro six points clear of the relegation zone, and the Granata seem to be on course to achieve their pre-season aim of avoiding relegation.