Antonio Candreva shot Salernitana towards Serie A safety on Saturday with his stoppage-time strike which secured a 1-0 win over Atalanta.
Under a torrential downpour in southern Italy Candreva won the match for Salernitana in the 93rd minute with a powerful low drive from the edge of the area.
The win puts Salernitana 11 points above Spezia, who are just inside the relegation zone and host Champions League chasers AC Milan later on Saturday.
Anything but a win for Spezia would secure Salernitana's Serie A status with three matches remaining.
Atalanta are seventh and five points from the Champions League positions, a gap that could be extended depending on how fourth-placed Inter Milan do against Sassuolo on Saturday night.