Cagliari moved level on points with Atalanta and opened up a nine-point advantage to the Serie A relegation zone with a 2-0 victory at the Stadio Sant'Elia.
Daniele Conti set the hosts on their way with an 11th-minute free-kick and Mauricio Pinilla made the points safe after the interval.
Cagliari goalkeeper Michael Agazzi had to be substituted early in the second half but Atalanta, despite plenty of possession, were unable to seriously test his replacement Vlada Avramov until deep into stoppage time.
Agazzi made an early save from Manolo Gabbiadini before, at the other end, Conti put the hosts in front with a fine curling free-kick into the bottom corner of Andrea Consigli's goal.
Consigli saved from Thiago Ribeiro and Radja Nainggolan before Atalanta enjoyed a spell of pressure.
Simone Tiribocchi shot just wide, Guglielmo Stendardo headed well over and Thomas Manfredini was also unable to test Agazzi, who was finally forced into another save by Luca Cigarini's long-range effort.
Consigli saved from Albin Ekdal and Conti then headed Andrea Cossu's corner wide, before Agazzi departed three minutes after half-time.
Carlos Carmona was keen to test newcomer Avramov but fired well wide from 30 yards.
And Cagliari eased their nerves in the 54th minute when Ekdal led a breakaway move which ended with Pinilla netting from close range.
Cossu shot wide and Ribeiro tested Consigli before the visitors again seized the initiative.
But Avramov saved easily from Tiribocchi and Carozza headed just wide from Maximiliano Moralez's cross.
Gabbiadini carried the fight in the last 10 minutes but shot over once and was twice denied by Avramov, including an excellent save from a free-kick in the 93rd minute.
