Gonzalo Bergessio's brace condemned Siena to another defeat as they basement boys let slip a half-time lead to lose at home to Catania.
The hosts looked like they could be on course to move out of the bottom three when Alessandro Rosina put them in front after 10 minutes.
Catania laid siege to the home goal, but it was not until five minutes into the second half that Lucas Castro levelled, with Bergessio completing the comeback 16 minutes later.
Bergessio got his second eight minutes from time to put the match to bed.
The defeat left Siena three points from safety at the foot of Serie A, while Catania moved up to eighth after bouncing back from back-to-back defeats.
The visitors had the first shot on goal as Francesco Lodi fired over from long range, but were soon behind.
Francesco Valiani counter-attacked down the left and crossed for Rosina, whose right-footed shot found the bottom corner.
Alejandro Gomez volleyed wide from the edge of the area and Lodi was off target with another shot as Catania looked for a response.
The visitors continued to boss the game and were only denied an equaliser by a goal-line clearance from Felipe Dal Bello, who headed Castro's effort off the line after the Catania man had rounded goalkeeper Gianluca Pegolo.
Sergio Almiron then fired inches wide as chances continued to come and go for Catania.
The Sicilians kept up the pressure after the break with Almiron going close again and Pegolo going full stretch to deny Gomez before they finally made the breakthrough.
Bergessio's excellent through-ball sent Castro clear and this time he beat Pegolo.
Both players were involved as Catania took the lead in the 66th minute, Castro running down the left and finding Lodi, who laid the ball off for Bergessio to slot home.
Pegolo then had to tip over an Almiron header, but Bergessio's second sealed the points by tapping in following a Castro corner.