Two second-half goals from Franco Brienza and Erjon Bogdani handed Siena all three points from their trip to Cesena this afternoon.
After Luca Ceccarelli had been sent off in the 70th minute for the home side, Brienza stole in two minutes later to put Siena in front.
Erjon Bogdani doubled his side's advantage in the 81st minute when he fired into the roof of the net from 12 yards out.
Siena continued to dominate as the match drew to a close, but they were unable to add to their winning margin.