Birthday boy Leonardo Pavoletti thought he had won the match for Cagliari, but Federico Bonazzoli pulled Salernitana level after 90 minutes.
The bottom two clashed at Unipol Domus in Sardinia on Friday night, both aiming to pick up three important points to kickstart their season after a poor start to the campaign.
But the performances justified the current situation in the table as neither side managed to create big enough opportunities to score in the first half.
It was an anxious match from both the Rossoblu and the Granata, when Keita Balde had the first real opportunity to score through an overhead kick.
Razvan Marin then tried from a free kick, but it only hit the side netting of Vid Belec’s goal, but the highlights were few.
Despite a difficult match in attack, the referee had enough work throughout the first half, as Daniele Doveri was called into action on many occasions.
Cedric Gondo was injured and replaced by Nadir Zortea, while Joao Pedro, who has been linked with a possible call-up for Italy, had a chance after 43 minutes.
The captain was at it again right before the half-time whistle, but Belec stopped his free header, which went straight at the goalkeeper.
Cagliari made one change at half-time, when Kevin Strootman replaced Alberto Grassi and Cagliari immediately looked stronger.
The home side were the most dangerous team in the second half, pushing for the first goal, but the two teams were as tense as in the first.
Then birthday boy Leonardo Pavoletti came on for Dalbert after 60 minutes and the physical striker made an impact on the Rossoblu attack.
Cagliari scared the guests with a few opportunities, but never really managed to test Belec until Pavoletti arrived at the first post.
Joao Pedro found the substitute Pavoletti on a run at the first post and the striker got a foot on the cross to give the Rossoblu the lead after 73 minutes.
Cagliari made some defensive changes, while Salernitana brought on Simy to replace Milan Djuric in attack.
The Granata finally hit the target for the second time in the match after 90 minutes, after long spells on the ball.
The ball arrived from the left and reached Bonazzoli at the far post and his finish found a way past Alessio Cragno in the Rossoblu goal.
Bonazzoli ruined the celebrations in Sardinia and made sure newly promoted Salernitana bring a point home in the relegation battle with the Casteddu.
Cagliari started 3-5-2 and Salernitana 4-4-2 Gondo on left (than Zortea), Obi on right (Obi and Zortea switch twice in 2.half)
After Pavoletti Subs. cagliari turns 3-4-1-2, after Scores turn back to 3-5-2.
with last 3 subs. Salernitana changed to 3-4-3