Mauri sends Lazio into Italian Cup semis
The midfielder thrashed in a loose ball with his left foot from outside the box six minutes after threading a pass into the area for substitute Goran Pandev to score the home team's equaliser at the start of the second half.
Captain Tommaso Rocchi then drove the ball into the bottom corner to wrap up the victory in stoppage time.
Defender Cesare Natali had opened the scoring for Torino, who are third from bottom in Serie A, just before the half hour when Lazio keeper Fernando Muslera made a mess of intercepting an Alessandro Rosina cross from the right.
Lazio next face the winners of the Feb. 4 quarter-final between Juventus and Napoli in Turin.
Serie A champions Inter Milan and Sampdoria meet in the other semi after they knocked out holders AS Roma and Udinese respectively on Wednesday.