Serse Cosmi's Siena grabbed a 1-0 win at home against fellow Serie A strugglers Bologna on Thursday night.
After a goalless first half in Siena, the home side took the lead in the 61st minute when Calaio unleashed a left-footed shot that deflected off a Bologna defender, bypassing the visitors' goalkeeper Federico Agliardi to hit the back of the net.
Bologna dominated Thursday's game with 59 percent possession and 14 shots to eight but Siena's Gianluca Pegolo made seven saves, including three after his team took the lead, to keep a clean sheet and earn the win.
Siena now have two wins and two draws from five matches but remain in the relegation zone due to a six-point penalty they received for their involvement in Italy's match-fixing scandal.
That leaves Siena on two points and in 18th position, while Bologna are 15th on four points.