Victor Ibarbo gave Cagliari the lead against a wasteful Udinese, whose hopes of snatching a point were dashed by further goals from Matias Vecino and Agim Ibraimi in the final 10 minutes at the Stadio Sant'Elia.
Both sides will end the weekend at least five points clear of the relegation zone.
Antonio Di Natale had two excellent chances to give Udinese the lead, the best coming in the 17th minute when Giampiero Pinzi cut into the penalty area form the right and pulled the ball back to the Italy international, who scooped his shot over the crossbar as he fell backwards near the penalty spot.
A minute later, Ibarbo put Cagliari in front, nodding Davide Astori's long ball into the air before turning in an instant and sweeping it into the bottom left-hand corner as it fell to the ground.
Di Natale went close again 10 minutes later, but Vlada Avramov got his fingertips to the ball to touch it onto the top of the crossbar.
Udinese kept trying to find a route into the game and defender Danilo headed just wide after an hour.
The visitors had to commit more and more men forwards and they were almost caught out by Nene in the 73rd minute, but he put his shot wide after an excellent delivery from the right from Ibarbo.
Five minutes later, Nico Lopez opted to cross rather than shoot, lifting the ball behind Di Natale when he had the goal at his mercy, as another good chance went begging.
Nine minutes from time, Vecino settled his side's nerves with a volley from the penalty spot as he ghosted into the area unmarked.
It was his first goal in Serie A, and a debut strike from Ibraimi followed in the last minute as he led a counter-attack and placed his shot in off the far post with three players up in support.